Increasing Phosphates

[Peyton]

I had been keeping phosphates around 1ppm since I set up my 40gal back in july. The tank had been algae free with the exception of green spots on the glass. Within the past month or so I started increasing to 2ppm, since many say green spot algae is an indication of low phosphates.

Well since I started increasing KH2PO4 the algae has went a out of control. I went from scraping algae once every two weeks or so to several times a week. It is also starting to apear on the leaves of my giant hygro.

Tank stats are 40gal with 110w CF lighting, 4 DIY CO2 bottles (two changed every week). 50% water change once a week.

Macros dosed sat, mon, wed.
1/4 tsp KNO3
8 ml KH2PO4 (was doing 4ml) ( a mix of 250ml water and 3 tsp of KH2PO4)
1 tsp k2SO4
and 1 tsp MgSo4 and 1/4 tsp CaSo4 dosed once a week after water change.

Micros dosed sun, tues, thur.
14ml Plantex csm+b (a solution of 250 ml water and 2 tsp csm+b

I have stuck with this schedule pretty well. The only thing I have changed really is the increased phosphate level. Am I missing something here?

[rkilling1]

Are you trying to dose EI?

How is the fish load and NO3 levels?

[Peyton]

Originally Posted by rkilling1

Are you trying to dose EI?

How is the fish load and NO3 levels?

Yep, I'm trying EI. For the first few months I tested everything. From that I got an average of what I should add. The fishload is fairly heavy. Have not tested NO3 levels. Before EI I did not add KNO3 either. The bioload gave me an average of 20ppm of N. A few suggested I add KNO3 regardless after I was having a some unexplained deficenties show up. I tested the first week after using KNO3 and N was at 60ppm but by then it was time for a 50% water change.

The deficentcy pointed to potassium which was hard to believe since I was adding to 20ppm per dose three times a week, not counting the K that was in the KNO3 I was adding.

[zenkatydid]

what test kits are you using? this sounds very odd.

[rich311k]

What are your CO2 levels running at? How steady are they? Something is out of balance. Extra phosphate would not cause an algae outbreak. Something somewhere is out of balance.

[Peyton]

I was using both Aquarium Pharmicaticals and Seachem test kits, but I have not used them for a few months since starting EI. My co2 levels as of right now are at 50ppm (190 ppm kh with a ph of 6.8). I would say ph stays that or higher with 4 diy co2 bottles going and right now two of them need changed out. Could it be I don't have enough light and too much CO2? With 110w CF over a 40gal thats just 10w shy of 3wpg. Could it be too much nitrates? Overdosing potassium? I don't really know how a tank could go from doing ok for 4 months using the same dosing schedule, to algae outbreak with just a increase in P being the only change.

I wish I could figure this out because it does not make sense. I'm going to go back to dosing 1ppm P to see if this helps. Any other suggestions?

Edited by An t-iasg to remove smilies from pH numbers.

[rich311k]

I would say either up the N or back off on the P. If you CO2 is steady, try testing a couple of different times during the lights on period. How long are the lights on? Have you tested the CO2 level in your tap after sitting out for 24 hours?

[fish_4_all]

Well if it helps, here is what I dose:
10 gallon, lots of plants ~33 watts of NO flourescent
1/8 tsp KNO3, .77ppm PO4, Sun, Tue, Thur
1/4 tsp MgSO4 and 1/2 tsp. Calcium citrate day of water change
I dose .27ppm CSM+B Mon, Wed, Fri

I no longer inject CO2 and have minimul green spot algae which I have to clean about twice a month if that. I also dose Excel every day according to the label.

If my snails show signs of problems or I see any fin problems I dose a little more MgSO4 (fins) and/or Calcium Citrate (snails) (going to get calcium chloride soon, citrate simply won't dissolve very fast)