Algae on top of water

cbster

cbster

AC Members
Nov 16, 2003
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Freeburg, IL
It seems like three days after doing a water change the surface of the water turns green and then I net it out and about three days later it happens again is there anything I can do to stop this the rest of the tank looks pretty good I have a slight bba problem that I just can't get read of but have SAE's to keep it at bay I dose 1.25 tsp. of Potassium Sulfate, .25 tsp. potassium nitrate, 1Tbsp. Magnesium Sulfate, 1/16 tsp. Mono Potassium Phosphate after 50% water change weekly and Flourish and Flourish Iron every other day (test Iron with Red Sea test kit but it always reads 0 the test kit is new but it always reads 0) then add Potassium Nitrate as needed every other day to keep it at 5-10 ppm. the tank is a 55 gallon heavily planted with 6 discus, 3 Cory cats, 4 SAE's, and 2 marbled hachetfish. I use RO/DI water and run a UV 24/7. if there is anything I should be doing different please let me know.

Tank perimeters
ammonia 0
nitrite 0
nitrate 10 ppm
PH 6.6
KH 3
GH 8
FE 0 (so the test kit shows)
PO4 1
 
You have no other algae issues anywhere in the tank, other than the green slick on the surface(not counting the BBA)?
Why do you run the UV?
What are your water parameters out of the tap (measured after standing out over night)?
You are using some unusual methods......just trying to figure out why. Also, why you have the surface problem and the rest of the tank is clear.
I've had protein slicks on the surface, but they weren't green and were cleared up with better circulation and the addition of Black Mollies.
Your K2SO4/KNO3 relationship is off, but don't know whether this is because of tap water issues with nitrates. That's the reason for the tap water question.
In plain English, Fe test kits suck. Very unreliable unless using Hach or LaMotte. What kind of plants are you growing that require extra Fe?

Len
 
The first thought I had was to nutrient starve your tank for a two week period.

Then I thought that maybe all that potassium in your water is contributing to your problem. From what I gather, dosing with KNO3 should be sufficient for Potassium. Not sure where your sulfates should be either excess sulfates may cause different types of Algae blooms than are normally experienced.

I would skip dosing everything for an entire week, but monitor your levels.
 
DJLEN and TORF

There really isn't much other algae in the tank that something doesn't eat or it doesn't grow. I don't really know why I run the UV I started running it because I had a bad green water problem and just keep it running. should I turn it off? and if so why? I use RI/DI water to get the Gh and Ph down for the discus so I really haven't checked it right out of the tap for awhile but I can if it would make a difference. I dose K2SO4 at 1.25 tsp. for 16.19 ppm and KNO3 at .25 tsp. for 2.6 ppm for Potassium and what I need for Nitrate. according to chuck's calculator I need 20 ppm potassium so if I am reading and dosing wrong please tell me. and I am dosing FE to try and keep it at 1 which is the level I have read it is suppose to be. I don't really have any plant that I know needs extra FE so should I just stop dosing it? the plants that I have are in my Aquarium specs.

Also I do a 50% to 70% water change every week so that should reset the tank pretty much for the next dosing regime.
 
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It would be a good idea for you to test your tap water for gH,kH,P and N.
Let it stand out over night and test. Then we will have a better idea of what we are dealing with as source water.
Fe that is not needed can be a problem. I would discontinue dosing it for a week, at least and see if you have a lessening of surface algae. You are getting what might be enough in the Flourish.
IME, it is best to make only one small change at a time to try to figure out what the issue is that needs to be corrected.
Forgive me if I missed it, but what is your lighting wattage, and are you injecting CO2?

Len
 
My lighting watts are 2.9 WPG regular fluorescent. and yes I am using pressurized co2. I checked my tap water and the water parameters are

PH= 8.4
GH=10
KH=4
Ammonia= .25
Nitrite= 0
Nitrate=0
Phosphate= 0.1
 
Did you test your tap water after letting stand out over night, and if so would you post the results of your tests for N,P,pH and kH.

Len
 
Yes that was letting it set overnight. also doesn't it take everything out of the water when you put it through a RO/DI unit or should I test that also?
 
What kind of NH3/NH4+ test kit are you using. You should be getting no ammonia out of the tap. Everything else looks good for use.
Hate to be a pain in the butt, but if you can, re-test for ammonia. Or take a sample (gassed out) to a reliable LFS and have them check for ammonia.
If that comes up .0 there is no reason why you can't use your tap water, even with Discus. Unless you are going to breed them, they should adapt well to your water. It's pretty soft, and with CO2 injection, you will be able to bring the pH down to reasonable levels for them.
Speaking of the Discus......part of your problem may be the body slime that they excrete. This can cause an excess of slime in the water table, and be trapping suspended particulates/algae at the surface.
If you can, adjust the return on your filtration to allow the surface to roll. Not to disturb it too much, but to get a bit more movement on top.
I think that you have some free floating algae (green water) that needs to be addressed in your dosing, and possibly the slime is trapping it as described above.
You haven't mentioned plants or plant mass. The heavier the mass, the more nutrients they will absorb. Something else that would help would be some floaters......Salvinia, Egeria, and Water Sprite would help quite a bit in sucking up the nutrients.
I would introduce them, cut out the Fe for a while, and see how it progresses.
Get rid of the algae and you can lose the UV. I am told that it is not conducive to nutrient dosing. I've never used one so I am not real familiar with it's ramifications.

Len
 
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