# Yellowing dwarf sag - lighting or soil deterioration?



## MSommerville (Oct 26, 2020)

I started my first natural planted tank in late October, so it’s coming up on 7 months now. Things have generally been growing fairly well, although I had trouble with stem plants not takin - I think because the lighting was insufficient. I added a second light about 3-4 weeks ago and most of the plants have responded happily to that addition.
However, my dwarf sag, which was previously doin great, has started fading and/or yellowing in the last week (see attached photo - exude the snail poop). I’m not sure if this is because it’s not enjoying the increased lighting, or if it’s possibly a lack of nutrients or the soil being depleted. When I planted, I realized later that the product is gotten was an organic potting MIX, not potting SOIL … I have no idea how much of a difference that would make.
Any thoughts on whether this is likely a case of the plant adjusting to higher lighting (in which case I would hope it will improve over time), or a depletion of the sibstrate (in which case I may be looking at needing to redo the tank sooner than I’d hoped)?


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## mistergreen (Mar 3, 2007)

If the fish population is low, it's probably lacking CO2 and nutrients. There's no harm in inserting root tabs under the sag.


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## johnwesley0 (Feb 23, 2021)

My understanding is that potting mix is primarily peat moss and some granules of glazed glass (perlite or vermiculite) that serve no purpose except to keep the mix from clumping. None of it has much in the way of nutrients. However, it could be useful for its ability slowly release CO2 within the substrate and to bind important nutrients like nitrogen and phosphorus to the roots of your submerged plants, if it has a high enough Cation-Exchange Capacity (CEC). All of which is a long-winded way of saying, you probably have to add fertilizer.


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## dwalstad (Apr 14, 2006)

Is there any fishfood input into this tank? If not, even the most nutrient-rich soil will give out at some point. Fishfood (after digestion by fish, bacteria, shrimp, snails, etc) provides nutrients once the soil's supply declines.

My first thought was that the Sag yellowing was a nitrogen deficiency, but if the stem plants are doing well and have good color, it must be something else. It could be that the substrate is generating H2S. Are you adding SeaChem Equilibrium or any fertilizers to this tank? 

Since potting mixes are sold to grow houseplants, they should contain plenty of nutrients. Thus, I don't think that your initial soil selection caused the problem. The increased lighting might have caused the paling, but I kind of doubt it.


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## MSommerville (Oct 26, 2020)

Thanks, and sorry, I should have added more information about what’s in the tank.

fish population is currently a little understocked, I think. The tank is 33g, and home to two Platty’s, 12 cardinal tetras (6 of them just added a few days ago), and 3 albino corydoras. There are also half a dozen (ish) neocaridina shrimp, and an indeterminate number of ramshorn snails. I’ve reduced my fish food input in the last few weeks in an attempt to reduced my ramshorn population … which, it occurs to me now, may go along with the timing of the decreased health of the dwarf sag. Hmm.
no fertilizers used (root tabs or liquid additives)
the only things I add are “salty shrimp GH/KH” (because I now only use demineralized bottled water on the tank - backstory below), along with nutrafin or seachem water conditioner and biological supplements when I add water.
water parameters are a steady pH 7.8, ammonia 0.25, nitrite and nitrates both 0, GH 9.
I poked at the soil this afternoon, particularly around the dwarf sag, to see if there was any gas activity - no bubbles from the substrate all. I haven’t been poking it for a few months because the bubbles noted after initial set up had essentially stopped.
As background to all that, I had treated this tank for hydra back in late February/early March. Treatment was tolerated by all residents, but then when I did water changes to clear the medication, my fish suddenly started dying (I posted on here about it at the time). Not sure if some sort of chemical in the town water caused it (spring being the time to flush water lines), or if it was some sort of delayed reaction to the medication and die off in the tank. Most of the remaining fish were moved out to other tanks, so the only current residents who were in the tank at that time are the Platty’s, shrimp and snails. Water parameters stayed fine afterwards.
Toward the end of March, I moved an adult corydora from another tank into this one (once I wasn’t feeling gun-shy anymore), and it did fine, but proceeded to kick up a whack load of snail poop all over the tank … which made me realize I had more snails in there than I thought I did, and that they had stashed of poop in places I wasn’t noticing … cue some water changes over the next couple of weeks (late March to earlyApril) to vacuum out as much as I could, along with manial removal of some snails and the reduced feeding I mentioned earlier. The cardinals and additional two corydoras have all been added in the last 6 weeks or so.
A picture of the overall tank is attached. The water’s a bit cloudy as I did some maintenance this afternoon and the Cory’s are continuing to make a mess. I’m planning to add a HOB filter just with filter floss in it to help clear that.


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## johnwesley0 (Feb 23, 2021)

First of all, your tank is beautiful. The fact that there are so many background plants doing well, including a giant cryptocoryne (?) which is known for its vast root system, makes me wonder whether we are witnessing a little bit of plant _allelopathy _or competition between species for scarce nutrients? Soil mixes are by definition commercial concoctions that have varying amounts of nutrients added according to formula. Bear in mind that they are designed to make potted plant owners buy more product eventually. Seven months may be pushing the limit of their usefulness as nutrient sources. Luckily, aquariums have access to an ever renewable source of ammonia (which is a favorite plant food) in the form of all sorts of critter poop. Vacuuming your substrate may not have been a good idea either, strictly from a plant's point of view.


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## MSommerville (Oct 26, 2020)

dwalstad said:


> Is there any fishfood input into this tank? If not, even the most nutrient-rich soil will give out at some point. Fishfood (after digestion by fish, bacteria, shrimp, snails, etc) provides nutrients once the soil's supply declines.
> 
> My first thought was that the Sag yellowing was a nitrogen deficiency, but if the stem plants are doing well and have good color, it must be something else. It could be that the substrate is generating H2S. Are you adding SeaChem Equilibrium or any fertilizers to this tank?
> 
> Since potting mixes are sold to grow houseplants, they should contain plenty of nutrients. Thus, I don't think that your initial soil selection caused the problem. The increased lighting might have caused the paling, but I kind of doubt it.


Do you suppose it’s likely to reverse or improve with increasing the feeding again (now that there are more fish, plus just trying to be more generous on behalf of the plants)? And am I ok to be adding some mechanics filtration to clear up the water column, or is that likely to be pulling more nutrients out and away from the plants? I’m hoping that eventually the Cory’s will get things to just mix in with the sand as they do their nosing-around thing, but I don’t particularly like the look of it getting kicked up ….


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## MSommerville (Oct 26, 2020)

johnwesley0 said:


> Luckily, aquariums have access to an ever renewable source of ammonia (which is a favorite plant food) in the form of all sorts of critter poop. Vacuuming your substrate may not have been a good idea either, strictly from a plant's point of view.


Thanks very much for your compliment on the tank! I hadn’t been thinking of allelopathy as an option here because most of the plants have been in the tank since the beginning (or near to it), and the sag has done well until now. The recent plant additions are hygrophila siamensis 53b (such a long name!), but the two plants are coexisting well in another tank I’ve got. But I suppose there is the possibility that there’s a combination of the sword plants and the hygrophila taking up more nutrients as the light has increased so they can grow more, and then that depriving the sag of some (beginning to have difficulty competing)?


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## johnwesley0 (Feb 23, 2021)

MSommerville said:


> Thanks very much for your compliment on the tank! I hadn’t been thinking of allelopathy as an option here because most of the plants have been in the tank since the beginning (or near to it), and the sag has done well until now. The recent plant additions are hygrophila siamensis 53b (such a long name!), but the two plants are coexisting well in another tank I’ve got. But I suppose there is the possibility that there’s a combination of the sword plants and the hygrophila taking up more nutrients as the light has increased so they can grow more, and then that depriving the sag of some (beginning to have difficulty competing)?


I don't want to get too far out in front of @dwalstad since she has also replied to this thread, but yes, it could be something like you describe. Seven months is not all that long for an established tank and the ecosystem sounds like it is still in flux, IMO.


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## klingy (May 21, 2021)

Try to use Seachem are professional preparations for these problems. Seachem Flourish Excel or Seachem Flourish Iron they are preparations that will definitely help plants


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## johnwesley0 (Feb 23, 2021)

klingy said:


> Try to use Seachem are professional preparations for these problems. Seachem Flourish Excel or Seachem Flourish Iron they are preparations that will definitely help plants


They already use Seachem with water changes.


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## dwalstad (Apr 14, 2006)

Nice tank. I would be very happy with what you have. I don't know if I would make any major changes such as adding a filter. I would feed more and let the substrate accumulate debris. That "debris" and "poop" contains nutrients (particularly iron and phosphates) that will feed your Sag.


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## jatcar95 (Oct 30, 2019)

MSommerville said:


> the only things I add are “salty shrimp GH/KH”


Does this product have any detailed ingredients on the packaging? Did some quick searching and couldn't find specifically what they use. I'm wondering if they use sulfates (similar to Seachem Equilibrium), in which case it could cause H2S toxicity.


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## alisonc (Mar 28, 2021)

MSommerville said:


> Thanks, and sorry, I should have added more information about what’s in the tank.
> 
> fish population is currently a little understocked, I think. The tank is 33g, and home to two Platty’s, 12 cardinal tetras (6 of them just added a few days ago), and 3 albino corydoras. There are also half a dozen (ish) neocaridina shrimp, and an indeterminate number of ramshorn snails. I’ve reduced my fish food input in the last few weeks in an attempt to reduced my ramshorn population … which, it occurs to me now, may go along with the timing of the decreased health of the dwarf sag. Hmm.
> no fertilizers used (root tabs or liquid additives)
> ...


I have found that there Is noticeable better growth rate for the plants that get constant gentle flow from a filter outlet than those in areas with very little flow, so your HOB with floss might help. I’ve not been anywhere near my tanks with a vac and they’ve been set up for around four years. I don’t seem to get mule or poop sitting on the gravel, it must get pulled down into the substrate as there is noting noticeable and I’ve never worried about it. I do have Malaysian trumpet snails that inhabited the substrate, which probably help to mix it in! I do water changes by scooping water out with a large jug to remove surface scum at the same time. It’s only 25gallons and only remove 5 gallons per water change So not too much of a pain. I think your tank looks lovely and everything looks healthy.


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## dwalstad (Apr 14, 2006)

MSommerville said:


> Thanks very much for your compliment on the tank! I hadn’t been thinking of allelopathy as an option here because most of the plants have been in the tank since the beginning (or near to it), and the sag has done well until now. The recent plant additions are hygrophila siamensis 53b (such a long name!), but the two plants are coexisting well in another tank I’ve got. But I suppose there is the possibility that there’s a combination of the sword plants and the hygrophila taking up more nutrients as the light has increased so they can grow more, and then that depriving the sag of some (beginning to have difficulty competing)?


I don't think your tank is plant-crowded enough to worry about allelopathy or plant competition for nutrients. I would stop using the "Salty Shrimp" and let mulm accumulate. Try some other means of increasing water hardness-- Wonder Shells, dolomite lime pellets, my recipe, oyster grit in a bag, etc. H2S toxicity originating from the Salty Shrimp is a possibility. You may have to due some sleuthing and experimenting here.


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## MSommerville (Oct 26, 2020)

dwalstad said:


> I don't think your tank is plant-crowded enough to worry about allelopathy or plant competition for nutrients. I would stop using the "Salty Shrimp" and let mulm accumulate. Try some other means of increasing water hardness-- Wonder Shells, dolomite lime pellets, my recipe, oyster grit in a bag, etc. H2S toxicity originating from the Salty Shrimp is a possibility. You may have to due some sleuthing and experimenting here.


Hi Diana. Sorry for the delayed response - I haven’t been back on lately. Came on this evening to give an update … I’ve been feeding more the last few weeks and have also added a few more fish to the tank. There’s one little area of the dwarf sag that is still looking a bit yellow-ish, but otherwise it seems to be greening back up. Not sure if it’s the increased nutrients or if it’s getting more used to the increased light, but it’s definitely doing better than it was.
As for the SaltyShrimp, I’d heard about it in a post on the forum here, and I guess I just have just assumed that it didn’t have sulphates in it (maybe??). My container doesn’t list ingredients, so I went on the SaltyShrimp website … and no ingredient list there either. So I think you’re right, I’ll need to do some sleuthing!


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## MSommerville (Oct 26, 2020)

alisonc said:


> I have found that there Is noticeable better growth rate for the plants that get constant gentle flow from a filter outlet than those in areas with very little flow, so your HOB with floss might help. I’ve not been anywhere near my tanks with a vac and they’ve been set up for around four years. I don’t seem to get mule or poop sitting on the gravel, it must get pulled down into the substrate as there is noting noticeable and I’ve never worried about it. I do have Malaysian trumpet snails that inhabited the substrate, which probably help to mix it in! … I think your tank looks lovely and everything looks healthy.


Thanks for this, very good to hear your experience. I’ve got pool filter sand as my soil cap, and I’m definitely thinking that the next time I set up a tank, I’ll go with a fine gravel instead. My Cory’s really like snuggling about in the sand, but then I think the poop tends to sit on top of it more than sinking down into it. I’ve wondered about adding MTS to the tank. I think I’ll give it a bit of time to see how things continue to settle, and then decide on whether or not to introduce some new snails.


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## ronnie (Feb 26, 2021)

MSommerville said:


> Thanks for this, very good to hear your experience. I’ve got pool filter sand as my soil cap, and I’m definitely thinking that the next time I set up a tank, I’ll go with a fine gravel instead. My Cory’s really like snuggling about in the sand, but then I think the poop tends to sit on top of it more than sinking down into it. I’ve wondered about adding MTS to the tank. I think I’ll give it a bit of time to see how things continue to settle, and then decide on whether or not to introduce some new snails.


Wanted to offer my two cents on the snails and Cory’s.

I definitely recommend MTS. They are burrowers and help move the waste and mulm on the sand to the soil below. I’m a firm believer in them as they help move the substrate around.

Concerning the Cory’s… I. Love. Corydoras.

I have a group of false julii’s in my el natural with small gravel as the cap. I check often and see no signs of it wearing down barbels. There is a lot of mixed opinions about it, but most Cory’s come (in the wild) from areas where there isn’t smooth substrate. (This creates heated discussion sometimes).

IMO, and from what I’ve read, it seems like water quality more than anything is what leads to barbel issues. With a naturally planted tank, there’s an ecological process constantly occurring which keeps anything from settling and going bad in the substrate (ideally). From this train of thought, we shouldn’t see issues if your tank is in balance.

In contrast, with a gravel only tank, fish waste and uneaten food settle into the gravel and isn’t doing much benefit. Hence having to vacuum. And if someone with this set up doesn’t keep up with everything, the breakdown of stuff in the gravel emits gases that could damage the Cory’s sensitive areas (barbels).

That being said, Cory’s obviously like digging in sand, but I watch mine dig in the smooth gravel everyday and they look healthy as ever.


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## spaquarista (Jun 23, 2021)

ronnie said:


> Wanted to offer my two cents on the snails and Cory’s.
> 
> I definitely recommend MTS. They are burrowers and help move the waste and mulm on the sand to the soil below. I’m a firm believer in them as they help move the substrate around.
> 
> ...


Here're 2 more cents! I have 7 corydoras (kanei variety) in a 30g and tons of MTS (and other snails) - I don't have gravel, I do have sand, but I don't clean the mulm ever - so I second this post! Mine are super healthy and happy, it's been months this way.


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