Get rid of algae on glass

[shaman]

Hi, may I know how to get rid of the algae that stick on the glass. Those are spot algae. How much potassium compound do i need to put?

[vinz]

You don't need potassium. You need phosphorus.

Dose Seachem Phosphorus or KH2PO4 to get about 1 to 2 ppm PO4 (read the seachem instructions carefully... you want ppm of PO4, not ppm of P).

What is your current dosing routine anyway? Your average tank temp? The warmer the water, the higher you should dose.

[shaman]

Hi the water is 24 celcius, I using seachem Excel. Dosing half cap everyday. Tank volume is 100 litres. light is 144W. about 4 wpg.
May i know how to calculate PPM? How many teaspoon? I got some of PO compounds in bags

[vinz]

To calculate the PPM, you need to know exactly what PO compounds you have. Then use a calculator like this or this to calculate.

I suggest you dose about 0.5 ppm every 2 days first, since you are not dosing anything else other then excel. Clean the glass and observe if the algae comes back or slow down over a week or so. If they come back, raise to 1ppm dosage, observe, raise again if necessary.

Dosing PO4 will drive up NO3 uptake. You might soon find that you'll have new algae issues due to lack of NO3, CO2 and/or other nutrients. The tank has a lot of light too for a unfertilised tank.

What plants do you have in there? How are they doing at the moment? You should consider using less light.

That said, take things step by step. Do the PO4 thing first. I'm forecasting doom and gloom (base on experience and readings), but if your tank works, don't mess with it too much.

[PeterGwee]

Hi the water is 24 celcius, I using seachem Excel. Dosing half cap everyday. Tank volume is 100 litres. light is 144W. about 4 wpg.
May i know how to calculate PPM? How many teaspoon? I got some of PO compounds in bags

Cut the lights or you would still have issues with lack of carbon. Excel is not going to cut it for a very high light tank since its only 1/3 strength of normal CO2 gas.

Regards
Peter Gwee