Going in circles - how best to control phosphate?

F

FishInMaryland

AC Members
Sep 30, 2004
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Davidsonville, MD
Problem: brown algae, diatoms, whatever you want to call it
From reading a lot of posts, I think this is diatoms, but am not sure of exactly what to call it. It's not outrageous, and tends to coat the walls, (silk) plants, and wood and rubs off easily, but is ugly and drives me crazy.

Over the 13 months I've had the tank in my house (which I bought lock, stock, and barrel from somebody), I've battled this problem and tried lots of different things. Now, I still have phosphates in the 10ppm range, and think this is the cause of the diatoms, but don't know where the phosphate is coming from.

Can somebody tell me the optimum setup for a non-planted tank to keep phosphates to a minimum? Temperature, watts of light, amount of time to leave lights on, type of air bubbler, etc. I can put in up to 230 watts of light, but currently have less than that - don't worry about how much is there now, please just tell me what I should have. Should I keep a phosphate adsorbing media in my filter at all times? Which one?

I can get the phosphates down to about 2 ppm through water changes and use of Phos Guard, but shouldn't it go lower than that? The tap water tests negligible for phosphates and it takes no time for it to go from 2 ppm back up to the 10 ppm range. It has to be coming from something, doesn't it? Is it just the fish poop causing the problem? How often should the filters be cleaned?

I had live plants for a while, but really struggled to get them the right environment, since we're on well water, and ended up spending tons of hours housekeeping to keep the algae down, and lots of money on various chemical fertilizers, mostly to no avail. Took out all plants in April, and just have 4 silk plants in there now. The tank and gravel are MUCH cleaner, algae problem is reduced, but still have the diatoms.


Currently:
- 125 gallon acrylic tank (different from glass, since all equipment has to enter the tank from one end - so all circulation, etc., comes from one end of tank)
- 2 Fluval 404 filters, the only media in them is ceramic rings, along with 4 of the Fluval spongey things in each filter.
- 15 W UV filter, however bulb is probably old and I can't change it, or I would have a flood
- temp is about 75-77
- PH is 7.8
- 50% water changes every 4 weeks, but clean off plants and walls in between, as needed. I vacuum the gravel when I do a water change, and it is not very dirty (not like it was when I had live plants).
- Feed a smidgen (1/2 tsp) once per day, using Nutrafin (supposedly has lower phosphate) and about 12 Hikari Gold cichlid pellets. It's all gone within 2 minutes.
- 8 blood parrot cichlids, about 3-5" each
- 3 bala sharks, 3-4" each
- 1 blue channel catfish, about 4"
- Several pieces of wood for aquariums
- Couple of rocks, which I've tested to make sure they don't give off phosphates
- Tetratec Deep Water DW18 pump, hooked up to about a 15" flexible air wand

Sorry for the long post. Thanks for any suggestions.

Ruth
 
It's hard for me to tell the difference between the shades of red at the bottom of the card...suffice it to say, nitrate is at least 40 ppm, perhaps even as high as 80. I did a 35-40 gallon water change 2 weeks ago.

I assumed when I got the tank, that I could stick to the same schedule that the previous owner did - 25% w/c every 4 weeks, clean alternate filters quarterly. And this was with an additional handful of relatively smaller fish.

What would you expect to be a "normal" w/c schedule, given the fish I have, etc.?

BTW, thanks for your response. Your wall-o-tanks and associated plumbing are quite impressive!
 
I have on rare occasion seen 25% once a month water changes published in supposedly credible sources, but most often see anywhere from 10-25% each week recommended. I change about 13% a week, but it's only one bucket, so does not take as much time and effort as a 125 gallon tank! Most often, I've seen manufacturer instructions call for replacing filter cartridges, or cleaning filter media once a month, if not sooner. Once a quarter is awfully infrequent, it seems to me, but I don't know what Fluval recommends. I would take the spongy things out of the filter when doing your weekly water change and at least rinse them in the old water. (This might be all that "cleaning" them entails anyway.)

Nitrates can also contribute to algae, and is typically a more common problem than phosphates as too high a nitrate level is due primarily to aquarium care practices. If your nitrates are actually 40-80 ppm, you need to get them under 40 ASAP with large water changes! 40-50 is the upper limit for freshwater in the test kit instruction and other printed publications, although it seems many here like to keep it under 20. If you are having difficulty differentiating the colors, you might want to try another test kit. Although I'm sure there are several good ones, I use the Aquarium Pharmaceuticals nitrate test kit. It will easily differentiate the ranges, and I've seen it in almost every fish and pet store I go into.


Perhaps changing the UV bulb will help, too. Those are supposed to be replaced quite frequently, and if your system is not plumbed to make that replacement easy, you might want to figure out how to do so.

Hope this helps. Let us know how you do.
 
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Thanks for the comments. I'll try to do 25% weekly changes, and will do a large change tomorrow. You're right - it's a nuisance in the 125 gal tank. We don't have enough water pressure (danged water saver faucets) to use the Python/waterbed thing, so it's hauling buckets for us. This requires me to get help from my husband. Had he known the maintenance required, he would never have agreed to get the tank!

Also, you're right about what "cleaning" the filters means. Along with rinsing out the spongey things in the old water, I swish around the ceramic pieces to get the crud out, then dump the old water and add fresh.

Do you have recommendations on the lights - how much and how long to leave them on?

I do have the Aq. Pharmaceuticals nitrate test kit - I think it's my eyes, not the card, that makes it hard to differentiate between 40 and 80 ppm!!

Thanks.
 
As already stated, either 40 or 80ppm is way too high. I try to operate at ~10ppm nitrate for planted tanks (some I do have to add nitrate, most I have to add phosphate).

It is kidding yourself to think that there is set percentage partial water change effective across a variety of tanks. Every setup is different, they are fed differently and the fish housed are different. Monitor nitrate production or phosphate accumulation and hit a schedule that works for you. that is the only way to find the appropriate percent partial that is good for your tank. Mine range from ~25% weekly to ~50% weekly (most of my tanks) these days, but I have operated setups requiring more than 100% weekly. I have gotten too lazy for that these days.
 
I do have the Aq. Pharmaceuticals nitrate test kit - I think it's my eyes, not the card, that makes it hard to differentiate between 40 and 80 ppm!!
Click to expand...

OK. In that case, you want to have the nitrates in the range where you have difficulty differentiating between 10 and 20 (or even 5 and 10 - where mine runs) rather than between 40 and 80. :)

Certainly get it in the 20-40 range right away..
 
OK, this morning I've done a 50-60% w/c and phosphate is down to 2-5 ppm, and nitrate is down to 20-40 ppm. I'll do another w/c on Thursday. I didn't do anything with the filters, since I cleaned one 2 weeks ago, and almost had a flood with #2 this morning. The old-old-style Fluval external canisters are a pain.

I still don't know about lighting. I've read that more light will help discourage algae growth, but people who have outbreaks almost always immediately go to a lights-out situation for a number of days. Any thoughts on wattage and amount of time to leave them on?
 
I'd suggest leaving the lights alone for now and concentrating on maintaining low nitrate /phosphate levels.
I say this for two two reasons.
For one thing, I suspect it will solve your problem, given some time ( 6 weeks?thats a wild guess)
secondly, it makes sense to change only one parameter at a time in order to learn whats really going on, which will be good for future.
 
I agree with all advice so far. Nitrates are too high, have you tested your well water for nitrates?

If you have no live plants, then I would turn the lights out all the time, except when viewing (few hours in the evening). Is there any sunlight leaking into the tank? It also might be worth noting that an algea problem to some people, might apear normal to others. Everyone has there own tolerance for that sort of thing. I noticed that you didn't mention any algea control fish. Even with my weekly 40% water changes, I still rely on ottos or rubber plecos to keep the tank looking spiffy.

Also , have you thought about anubius, java fern, bolbitis, jova moss. These are live plants that you would be hard pressed not to grow and when arranged properly can look fantastic. There is a 300g planted display tank at my lfs that people are always saying "wow, I bet you need alot of light for that" . Well there is alot of light and co2 on that tank, but on closer inspection 75% of the plant mass is made up of the plants i mentioned above artfully arranged to showcase a very few "high maintainance" plants. Just about anyone with a 1-2 watts/gallon could come pretty close to duplicating it.
 
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