# Best media for removing silcates and phosphates?



## CatG

Ok, I am in the middle of a diatom outbreak. I've done 3-50% water changes in the last week and a half, and the stuff starts piling up again within about an hour after the water change. My plants are covered with a thick dusting of the stuff, the water is somewhat cloudy, and eveything looks dingy and dirty.

From what I've read, this is fairly common for newly cycled tanks, which mine is. However, I also read that silicates and phosphates are part of the problem and I am worried that these may be present in my tap water. If they are, then doing water changes is simply providing the diatoms with a fresh food source. I can't afford to go buy distilled water, as I would have to buy about 30 gallons at a time, and I also don't want to spend money on any of those units (RO units?) because they are too expensive.

So, I've seen a few different types of filter media I can get to remove phosphates and silcates, but am unsure as to which to get. Some of them appear to be little tiny pellets you put in your filter, but they don't seem to come in any sort of mesh bag. Do I need to put these in a mesh bag to be able to put them in the filter? They look pretty tiny, so I think they would fall out of the filter baskets if they weren't in a bag. If they need to be in a bag, where do I get them?

I have also seen silicate removing filter pads that you cut to size, but do these also remove phosphates?

Which would be better, the filter pads or the tiny pellets?

Also, I am using macro ferts that contain (among other things) potassium phosphate. Is this adding to my problem? Should I mix up a new batch and not include the potassium phosphate?

Here are some general specs for my tank. I can provide more detailed info if necessary:
75 gallon long tank
moderately planted
~2wpg via 4 lights - 2 reddish spectrum, 2 blueish spectrum
photoperiod - ~8.5 hours
Fluval 304 filter
Penguin 550 powerhead
4 albino corys
4 otos
1 siamensis
malaysian trumpet snails, some ramshorn snails, and some other kinds of snails (snail populations have exploded - the only snails I actully put in there were the MTS, the others came from plants)

Thanks,
Cat


----------



## nokturnalkid

Don't worry about removing phosphates. Unless you have an unreasonably high ppm of phosphates, tested with a calibrated test kit, adding phosphate shouldn't be a problem. Plants will use them up easily. As for your silicate problem, I wouldn't worry about those silicate removers. They work, they just aren't needed. Just keep up with the water changes and they will go away. I like to use one hand and "brush" off the diatoms while the other hand is holding the siphon nearby to suck it all up. Also, get yourself a few more ottos, maybe 4 or 5 more. They will help gobble diatoms like its no tomorrow. Keep up with maintenace(wc, cleaning filter media, trimming, etc.) and your tank will eventually balance itself out.


----------



## Newt

Seachem makes a product called PhosGuard and it removes both.
I have some I dont use anymore and might consider selling it.


----------



## CatG

Thanks for the responses!

It seems the brown algae IS starting to go away. I guess I just kind of freaked out when I saw everything covered in that suffocating layer of brown dust. There's still some in there, but not anywhere near what was in there a week ago. Hopefully it is on it's way out for good.

So, for now I guess I will leave things as they are since it seems to be going away. I was just afraid that there were silicates in the tap water, which I figured would just perpetuate the problem.

I do have another question though. Would a large brown algae outbreak affect my KH and GH? My KH has dropped from the steady 3 that it was, down to 2. It's been steady at 3 since I set this tank up a few months ago. In doing a little research, it said large amounts of organic waste would cause the KH to drop, and I wondered if the dying brown algae was to blame. My GH has also dropped from a pretty steady 9 down to 6. Not sure if the algae would have caused this. Any thoughts?

Thanks so much,
Cat


----------



## Diana K

Diatoms themselves ARE silicate filters. They are removing the silicates from the water. You simply need to stay on top of removing the Diatoms. Every time you remove a lot of Diatoms you are also removing a lot of silicates. 

New glass tanks and sand substrate are high in silicates and can load the water so much that Diatoms will thrive for a month or two in a new set up. The more frequently you remove them the more silicate you are removing from the system. If you let the Diatoms die the silicate is recycled into new diatoms. 

If you think there is really an issue with your tap water then prepare the tap water ahead of time. Fill a garbage can (Rubbermaid Brute, 32 gallon on wheels) and run a filter on it with whatever silicate/phosphate remover you find works for you. Then use this water for water changes. 

Fine pelleted media can be used in a filter by placing the media in a nylon stocking. I can get 2 large bags or 3 small ones out of a single knee hi stocking.


----------



## EValP

I would just grin and bare it with the diatomes. I tried PhosGuard and it didn't make any difference, it got worse actually. lol

It is somewhat difficult and expensive to eliminate this and with time it disappears leaving no real trace. It took about 3 months for mine to fully die and the tank to start having predictable levels of anything but in my limited knowledge, I would not think that the diatomes would effect GH or KH. Maybe someone with more experience could weigh in.


----------



## Coralite

Best media for removing Silicates hands down is a product called Silicarbon from Germany that is available from Aquarium Specialty.


----------



## Diana K

You have been doing a lot of water changes. (not a problem!). 
Have you tested the tap water for GH and KH? Perhaps the tap water has gone softer. Then the water changes are having a net result of softening the water in the tank. 

Plant use the calcium and magnesium that we measure as GH. I don't know about using it that fast, though!

Some plants can use KH as a source of carbon when CO2 gets too low. 

The other issue might be the test kits. When the difference is 1 degree of hardness (either GH or KH) it is difficult to say what the real hardness is. Either test might be right. 1 degree is not enough of a difference to worry about. 

3 degrees does sound like something is happening, and keep looking for answers. 

Yes, the microorganisms that decompose organic matter need some minerals to do their work. This might be part of the reason these numbers are dropping. 

To raise KH add baking soda. 1 teaspoon per 29 gallon tank raises the KH by 2 degrees. 
To raise GH use Seachem Equilibrium or Barr's GH booster. Per the Equilibrium label: 1 tablespoon per 20 gallons will raise the GH by 3 degrees. It also includes some potassium and other minerals that the plant use.


----------



## CatG

Thanks so much for the advice and suggestions!

Diana,
I had a base line for the tap water when I first set up the tank, but never thought about checking it again. Thanks so much for the suggestion! They have been replacing water lines in my area within the last couple of weeks, so maybe that has something to do with it. I will run some tests to see what, if anything, has changed. I guess it's possible that the old lines had mineral deposits built up on the interior, which could have introduced more minerals into the water. With brand new clean lines, they won't have the buildup, which I guess could change the water parameters. Not sure that that is the case here, but I running more tests is definitely a place to start.

Thanks again!
Cat


----------

