Why Won't My Phosphates Go Down?

[aquaticadmirer]

I've been having this problem in my 55g tank for a while and I just can't seem to figure out how to lower my phosphates. It started a long time ago as my tank was neglected for a while (I was away at school and my brother was caring for it). I was trying to get the tank back in order and used a whole bunch of phosphate buffer to bring the pH up. Since then I've learned it's better to just bring it up with water changes, but unfortunately I was ignorant at the time.

Anyway I started having an algae problem and just treated the symptoms (frequent scrapings..). Then I decided to change the tank a little and replaced the green colored gravel with natural brown gravel. Then all of a sudden my problem switched from algae to diatoms, which I've read is probably due to the extra minerals that were added with the new gravel. The tank only takes about a week to go from crystal clear with clean decorations to brown and murky with decorations covered in diatoms.

After I changed the gravel I bought a phosphate tester and it's off the charts. The tap consistently tests at about 2ppm while my tank has consistently tested at 10ppm, which is as high as the tester goes, so who knows how high it actually is!

So far, I've used 500ml of Seachem Phosguard on the tank to try and remove the phosphates, and the level hasn't dropped at all. I do about 35% water changes once a week, and it's been about 3 months since I stopped adding buffer and 2 months since I changed the gravel (so about 12 water changes have been done since I added the buffer, which you would think would have diluted it somewhat). The only chemicals I use are Prime, AcurelF (a water clarifier that works amazingly well to clear the brown murkiness), and the PhosGuard.

These are my water readings, as of about 5 minutes ago:
pH: 6.8
ammonia: 0
nitrite: 0
nitrate: 10
phosphate: 10+

The fish are all very healthy and I haven't had any other problems, but the tank just looks so nasty! Any help or advice on what else I might be able to try to get the phosphates down would be greatly appreciated!!

 

[aquaticadmirer]

anybody else have any problems like this?

 

[steelhealr]

Any phosphates in your additives? In general, I don't recommend adding anything to your tank. Using a clarifier only means that you are treating the symptoms and not the problem.

In marine, we sometimes use a phophate reactor....a tube filled with a phosphate binder that has water pumped thru it. Filter pads (not filter fiber) bind phosphate as well.

Something is adding phosphate to your system...you may be overfeeding. Food contains phosphates. SH

 

[rdd1952]

Never had a problem with them (actually never measured but a couple times when I first set up my tank and had some algae issues). Here is a pretty good article about where they come from.

 

[aquaticadmirer]

Any phosphates in your additives? In general, I don't recommend adding anything to your tank. Using a clarifier only means that you are treating the symptoms and not the problem.

In marine, we sometimes use a phophate reactor....a tube filled with a phosphate binder that has water pumped thru it. Filter pads (not filter fiber) bind phosphate as well.

Something is adding phosphate to your system...you may be overfeeding. Food contains phosphates. SH

I agree that it's better to treat the cause and not the symptoms, and that's definitely what I'm trying to do. I'm just using the clarifier in the meantime so I don't have to look at a brown murky swamp in my bedroom!

The bottles of Prime and AcurelF don't say anything about phosphates, so I'm going to try and contact the companies to see if they contains phosphates. I feed a moderate sized pinch daily for a fully stocked 55g tank, which the fish eat within a minute, but maybe I'll try feeding a little less and skipping a day of feeding and see if that changes anything.

Based on my quick investigation, it seems like phosphate reactors are either beyond my scope of DIY or beyond my budget. I use Penguin filters that are fitted for pre-made cartridges but I might try and modify them with filter pads or just put a filter pad on top of the existing fiber.

Thanks for the tips so far..anybody else have any ideas I haven't thought of yet?

 

[InaneCathode]

UV Sterilizer would help, wouldnt it? Diatoms are originally spores/cells in the water column that can be killed, right?

 

[rdd1952]

Have you tested the phosphate level in your tap water? Could be that it's in the tap and there's nothing you can do.

 

[Darkstar]

Do you use carbon in your filter?

 

[smmetz]

I have used "Kent Marine Phosphate Sponge" with success in greatly reducing phosphates. It is a fairly fine white gravel. I just put it in a bag of some sort (many people recommend making a bag from womens stockings), and put it in the filter. Like carbon, it needs to be rinsed first to remove any powder in it.

BTW, although this product did reduce my phosphates, it did not resolve my algae issues by itself. I added a timer on my light and reduced feedings to once per day from twice per day. My green water then went away.

 

[aquaticadmirer]

Inane, I've thought about a UV sterilizer before but they're a little expensive for me right now. I might just splurge and get one anyway though, but not before researching and making sure they're effective against diatoms.

rdd, I have tested the tap and it tests at about 2ppm consistently. But the tank tests at 10+ consistently so it can't be all from the tap. I'm just trying to figure out other sources that it could be coming from.

darkstar, I do use carbon in my filter. Does that contribute to phosphates?

smmetz, do you know how high your phosphates were before you started using the sponge? Mine are pretty high so I'm thinking that the phosphate removers I have used so far just absorbed to capacity and couldn't impact it enough to reduce the readable levels. It might be useful to try a different brand though and see if that seems to work better than what I've been using.

 

[Danno]

Your PhosBan might be completely depleaded of space to hold more phosphates. You might have to remove that amount you have in your tank and get fresh baggie full. Once the baggie of PhosBan is full it is just like having a trickle of phosphates going in your tank.

 

[rdd1952]

I know you're doing lots of water changes to try to solve the problem so this probably isn't a factor but do you ever just top off the tank when water evaporates? That can lead to higher levels as things like nitrate, phosphate, etc don't evaporate with the water. So when you top off, you are acutally allowing them to build up if they are present in your tap water.

 

[Darkstar]

darkstar, I do use carbon in my filter. Does that contribute to phosphates?

yes carbon does release phosphates. As a general rule, and as I understand it, the more expsensive the carbon the less phosphates it will generally release...but yes, all carbon releases phosphates to some degree.

 

[smmetz]

To answer your question, my phosphates in were only about 2 in my 55 gallon tank. I put about 1 cup of that product inside a filter cartridge (was using a whisper 60 filter at the time), and it did the trick for me.

 

[aquaticadmirer]

rdd, no I never just top off the water. Even before I was having a problem I always took some water out before putting more in, exactly for that reason. So that's not the problem, but thanks anyway!

Darkstar, I never knew that carbon can release phosphates, so that might be part of the problem. I have two filters on the tank - a Penguin 170 and a Penguin 330 - which is more than enough filtration for the tank. I change the ready made cartridges with Marineland carbon in them, which I think is pretty good quality carbon, about every 2-3 weeks. The 330 also has bins in it where you can put extra media and while they've recently been filled with PhosGuard, I sometimes put extra carbon in them. The extra carbon was cheaper so that might be some of the problem.

I guess for now I'll take everybody's advice, and keep replacing the phosphate removers and see if it starts going down! Thanks everybody!