# 75 gallon low light - nitrate deficiency



## jschall (Apr 13, 2009)

*75 gallon low light - nitrogen deficiency*

I have a 75 gallon which is pretty well-stocked:
One 8", two 6", and a 4.5" bichir, three 10-12" ropefish, three 3" and six 1.5" congo tetras, 6" african knife fish, and a 3" african butterfly fish.
I feed them fairly liberally, about 20 3mm pellets every day for the bichirs and a few liberal pinches of flake for the congos and butterfly.

Here's a picture of how it is planted:
http://jonathan.challinger.net/fulltank.jpg
There's 64 watts of t8 over it.

The anubias has shown signs of nitrogen deficiency (putting out a tiny yellow leaf), and I have been having BBA and cyanobacteria issues. The bolbitis on the right in that picture is almost completely gone now, I destroyed it with h2o2 trying to kill BBA and had to trim almost every leaf off of it.

I'm running purigen in the filter, and I do a 50% WC every week. I took my water to be tested at a LFS (my API test kit is expired) and they said I had no nitrate.

I assume the BBA is probably caused by excess phosphate because the plants don't have any nitrate. So, what I've started to do is add 1/4 tsp KNO3 after my water changes. It's too early to tell if it will work (the anubias has put out new leaves but they're still very small leaves) but I just wanted to ask here if I'm doing the right thing, or if I should be adding more or less KNO3, or removing the purigen, etc...


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## Philosophos (Mar 1, 2009)

To be honest, you've got a very sparsely planted tank with fairly low light. Dosing beyond perhaps trace and K+ shouldn't be necessary; perhaps not even that if you've got hard water.

First, take out the purigen; it's designed to rip nitrogen out of the water.

Next, increase your circulation. The BBA won't hang around if you've got decent current and O2 levels.

From there, scrub out the algae, do a 70% WC, then another in a couple of days. Suplement with a 1/2 EI dosing of KNO3/KH2PO4/micros after each change, run a week that way, then back off and let the food do its job.

Once you've done this, you'll have recovered from the algae and purigen issues. You'll be able to get a more accurate look at whether food and tap alone will supply what you need. With a tank like that you can probably back off to 50% WC's 1-2x a month unless you're doing it for the sake of the fish. It's easier to provide nutrients through feeding if you change the water less often. If you want to keep up the 50% weekly water changes, I'd personally dump in nutrients at a 1/4 EI rate.


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## jschall (Apr 13, 2009)

Philosophos said:


> To be honest, you've got a very sparsely planted tank with fairly low light. Dosing beyond perhaps trace and K+ shouldn't be necessary; perhaps not even that if you've got hard water.
> 
> First, take out the purigen; it's designed to rip nitrogen out of the water.
> 
> ...


I am indeed doing WCs for the sake of the fish.
I'd love to keep the purigen (I don't like brownish yellow water from tannins), and it shouldn't take up inorganic nitrogen (such as from KNO3)
You think O2 is important with BBA? I've heard everything now: not enough CO2, O2, too much phosphate, too little nitrate, too little water movement, too much dissolved organics (isn't that what purigen removes?) and "just make the plants happy."


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## Philosophos (Mar 1, 2009)

Ah, sorry typo; BGA not BBA. BGA doesn't do well with high oxygen/flow.

BBA is what happens when you have mid to high PAR values and not enough CO2, plain and simple. The equilibrium point for any nutrient on any algae is lower than any vascular (and probably non-vascular) plant that I know of. If you're dosing anything useful to plants, algae will out-compete. The only way I know to cope is to go non-limiting for plants to give them their best chance. Of course, "Non-limiting nutrients, Light limited tank" has become the mantra for enough of the hobby.

Anyhow, given the purigen I'd dose 25-50% EI myself. Might as well given that if the WC is for the fish, you're feeding them daily anyhow (or more perhaps), and the ferts aren't much more work.


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## jschall (Apr 13, 2009)

Philosophos said:


> Ah, sorry typo; BGA not BBA. BGA doesn't do well with high oxygen/flow.
> 
> BBA is what happens when you have mid to high PAR values


<1wpg T8s


> and not enough CO2, plain and simple.


So should I just inject CO2? Problem is, I've read posts talking about BBA growing right on the sponge of one of those hagen mini elite filter DIY CO2 reactors.
I already did switch the lights to a siesta period (to give CO2 a chance to build back up mid-day) and rotated my spraybar so that there's more surface movement.
I haven't noticed any new BBA on the spraybar or on the plant I trimmed.
Will the BBA die by itself if conditions change to unfavorable?


> The equilibrium point for any nutrient on any algae is lower than any vascular (and probably non-vascular) plant that I know of. If you're dosing anything useful to plants, algae will out-compete. The only way I know to cope is to go non-limiting for plants to give them their best chance. Of course, "Non-limiting nutrients, Light limited tank" has become the mantra for enough of the hobby.


I don't understand how algae is inhibited in a tank with conditions that plants thrive in.



> Anyhow, given the purigen I'd dose 25-50% EI myself. Might as well given that if the WC is for the fish, you're feeding them daily anyhow (or more perhaps), and the ferts aren't much more work.


Well, I'll keep up the KNO3 dosing at 33% EI. I think the fish food is plenty of phosphate, and I'm not sure that purigen is as effective at removing phosphate as it is nitrates.


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## wet (Nov 24, 2008)

I know some might call this cheating, but how about removing the BBA'd sponge and giving it some hydrogen peroxide or glut./Flourish Excel or a bleach soak and dechlor rinse?

I agree with removing the stuff in your filter soaking up nutrients. Low - moderate light with plants as filters definitely works. Think what Walstad would do. Fill in the gaps in the water column and, if possible, control with whatever percent water changes are convenient when you're not using a nutrient rich substrate. Check this out: http://wet.biggiantnerds.com/ei/con_v_time.pl

But before doing this I would add a faster grower that shapes well. I like your tank. What about some H. difformis you can shape? Might even help hide the intake. Its color would look good in there. Such a plant almost always helps, even when looking at deficiencies because it gives you a buffer with any dosing. Remember trimming removes un/measurables for the tank/system, too.


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## Philosophos (Mar 1, 2009)

<1 WPG of T8 with BBA showing up would make me want to check for NH4 issues, especially paired with BGA. On the other hand, if the bulbs are within their first 3 months then the output could be 50% higher, you'll also see another 50% more PAR out of a certain phillips bulb if you happen to be using that brand.

I've had BBA pop up directly in the path of compressed CO2; the presence of bubbles doesn't indicate high saturation if the bubbles have just gotten tossed in with a bunch of CO2-deprived water from around the intake only a fraction of a second before. BBA is so linked to CO2 that I can troubleshoot my CO2 flow based on it. If it's still around under conspicuous conditions, then I look directly to NH4 and maybe give my filter a clean.

Why algae is inhibited by non-limiting nutrients is something of a toss up. The observation has been made so repeatedly throughout the hobby that it's hard to ignore; there's a point of causality even if it's indirect. It takes a lot of money to test the hypothesis, and research grants to actually CULTURE aquatic weeds that every other scientist is trying to kill are kind of hard to find. The two bits of conjecture I lean towards would be germination signaling and autoimmune, neither of which are exclusive to the other. 

Germination signaling would be the concept that algae in nature would be at a disadvantage to reproduce when plants are providing heavy competition, and every other algae's requirements would be met. On the other hand when things are out of balance (nutrient levels change with the seasons) and not favoring competitive species, reproduction wouldn't happen.

Autoimmune is largely my own thing at this point, and it probably won't be tested for a long while. I figure there's some capacity for certain species to have allelopathic chemicals in their reduced cuticles that are high enough to prevent attachment. It wouldn't apply to every species, but it would explain why I don't see some types of algae grow on some plants. Some of the numbers are promising, but I'd need to pull dry weight analysis on plant cuticles to prove anything (got $500 for one analysis?)

Don't fear the phosphate. EI doses it up to 11ppm and rather than algae, you'll find GSA won't hang around.


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## jschall (Apr 13, 2009)

wet said:


> I know some might call this cheating, but how about removing the BBA'd sponge and giving it some hydrogen peroxide or glut./Flourish Excel or a bleach soak and dechlor rinse?
> 
> I agree with removing the stuff in your filter soaking up nutrients. Low - moderate light with plants as filters definitely works. Think what Walstad would do. Fill in the gaps in the water column and, if possible, control with whatever percent water changes are convenient when you're not using a nutrient rich substrate. Check this out: http://wet.biggiantnerds.com/ei/con_v_time.pl
> 
> But before doing this I would add a faster grower that shapes well. I like your tank. What about some H. difformis you can shape? Might even help hide the intake. Its color would look good in there. Such a plant almost always helps, even when looking at deficiencies because it gives you a buffer with any dosing. Remember trimming removes un/measurables for the tank/system, too.


The BBA is not on a sponge, it's on driftwood that has an anubias on it.

The tank is a west african biotope so I don't really want to add an indian plant.
I like the purigen, it keeps my water sparkly. Although, I'm not sure how necessary it is with weekly 50% changes.


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## jschall (Apr 13, 2009)

Philosophos said:


> <1 WPG of T8 with BBA showing up would make me want to check for NH4 issues, especially paired with BGA. On the other hand, if the bulbs are within their first 3 months then the output could be 50% higher, you'll also see another 50% more PAR out of a certain phillips bulb if you happen to be using that brand.
> 
> I've had BBA pop up directly in the path of compressed CO2; the presence of bubbles doesn't indicate high saturation if the bubbles have just gotten tossed in with a bunch of CO2-deprived water from around the intake only a fraction of a second before. BBA is so linked to CO2 that I can troubleshoot my CO2 flow based on it. If it's still around under conspicuous conditions, then I look directly to NH4 and maybe give my filter a clean.
> 
> ...


Interesting.

Bulbs aren't new, and I would be very, very surprised if I had ammonia. My water supply is well water, so there's no chlorine/chloramine to kill beneficial bacteria and no chloramine to break down into ammonia.

So you think I should inject CO2?


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## Philosophos (Mar 1, 2009)

I think with BBA showing up under old bulbs and <1wpg of T8, with low odds of ammonia, it's pretty amazing that BBA is even in your tank at all; maybe it's been holding over from some prior conditions. If you push it past equilibrium, it will slowly die off IME (months). I've found a little spot treating of Flourish Excel/Cidex/Metricide gives it a good kick in the right direction though (2 days to a couple weeks).

CO2 is something I think everyone should do. Compressed is preferable, but DIY is the next best thing. On a tank that size you may want to upgrade to a monster batch (3-6x?) and try to reduce surface flow to a very gentle ripple. If you use timers, you can always put your CO2 injection on one timer, and an air stone to run at night. You can always aid CO2 with regular glutaraldehyde dosing. If you're good with hazardous materials, work from pure, if you're not then buy Metricide or Cidex (figure out your best price per ml given their respective concentrations). Excel is way out of line in terms of price for dosing a 75 gal.

Well water is tricky stuff. It's pretty much a wild card from what I've seen of others experiences.


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## jschall (Apr 13, 2009)

Philosophos said:


> I think with BBA showing up under old bulbs and <1wpg of T8, with low odds of ammonia, it's pretty amazing that BBA is even in your tank at all; maybe it's been holding over from some prior conditions. If you push it past equilibrium, it will slowly die off IME (months). I've found a little spot treating of Flourish Excel/Cidex/Metricide gives it a good kick in the right direction though (2 days to a couple weeks).
> 
> CO2 is something I think everyone should do. Compressed is preferable, but DIY is the next best thing. On a tank that size you may want to upgrade to a monster batch (3-6x?) and try to reduce surface flow to a very gentle ripple. If you use timers, you can always put your CO2 injection on one timer, and an air stone to run at night. You can always aid CO2 with regular glutaraldehyde dosing. If you're good with hazardous materials, work from pure, if you're not then buy Metricide or Cidex (figure out your best price per ml given their respective concentrations). Excel is way out of line in terms of price for dosing a 75 gal.
> 
> Well water is tricky stuff. It's pretty much a wild card from what I've seen of others experiences.


I don't want my vallisneria to melt.
I'd love to do pressurized but I can't afford it. DIY is a bit of a pain, and mine has been dying down in less than 2 weeks. I'll try to find some brewer's yeast or champagne yeast.


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## Philosophos (Mar 1, 2009)

Alternative yeasts are always good for DIY CO2. So is doing yeast culture changes with the WC's; 30% weekly or 50% every 2 weeks turns it into a much more stable system.

Vals are a big limitation IMO. They're the only widely available, easily kept plant that melts from glutaraldehyde. There are other grass-like plants out there that you can look for that will not limit you in this way. Sagitaria subulata is simple but it won't melt on you, and it will fill out your tank faster than most other plants. I'm not saying dump the vals off, but keep an eye out in the future so that you can see the difference glutaraldehyde makes. 

If you want to stick with val as a genus, you might as well try out some of the non-vasculars that don't get along well with the stuff either; Fissidens spp. sure beats java moss.


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## jschall (Apr 13, 2009)

Philosophos said:


> If you want to stick with val as a genus, you might as well try out some of the non-vasculars that don't get along well with the stuff either; Fissidens spp. sure beats java moss.


The tank is a congo river basin biotope (that's what I'm going for, anyway. I'm not sure if I've actually achieved it or not)


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## Big_Fish (Mar 10, 2010)

jschall Check your PM... brewers yeast OTW.


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## jschall (Apr 13, 2009)

BGA is starting to bloom on my substrate, so I added 1/2tsp kno3, in addition to the 1/4tsp I added after my weekly WC on sunday and on tuesday and thursday.

Although, since I rotated my spraybar for surface movement, there's not as much movement on the substrate.

I'm going to try to get the water tested for phosphate.


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## jschall (Apr 13, 2009)

jschall said:


> BGA is starting to bloom on my substrate, so I added 1/2tsp kno3, in addition to the 1/4tsp I added after my weekly WC on sunday and on tuesday and thursday.
> 
> Although, since I rotated my spraybar for surface movement, there's not as much movement on the substrate.
> 
> I'm going to try to get the water tested for phosphate.


The LFS didn't have a phosphate test kit open, and I didn't want to drop $20 on one.
I did get nitrate done (they have a much more accurate nitrate test kit than I do, mine is the garbage API one) and it is 5ppm. Fertilator says: 1/2tsp kno3 in 75 gallons = 5ppm. So, the 1/2tsp kno3 that I added today was all that was in there. Which means, the extra nitrate I've been dosing had ALL been uptaken. I added another 1/2tsp so I should have 10ppm now.
Is it these vals? They were recently added to the tank. I added a lot of them, and they're spreading like CRAZY. I just can't see some anubias and bolbitis taking up very much nitrogen.

I'll up the KNO3 dosing to 100% EI, but I'm still not going to add any phosphate, since cyano typically means phosphate is too high from what I've read. I'm dosing the recommended weekly dose of flourish (the comprehensive one), as well. Should I bump that up to 2 a week?


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