Sugar dosage question

[michaeldaly]

I have been dosing sugar in my tank for quite a while now the tank is a 65g how high can I go with the dosing before it gets dangerous. Currently I have on occasion gone up to a heaped tablespoon with no ill effects.

[boxfishpooalot]

sugar will use up somthing like 50ppm of oxygen per tsp of sugar in 50gallons. A tank is full around 6-8ppm of oxygen. Things like protein skimmers and photosythesis may prevent oxygen starvation.

The oxygen drop is huge and 1tsp for a 65gallon(wich actually has probably only 50gallons in it) is dangerous.

I think sugar can be used but in small amounts over extended time periods. Like add 1tsp over 12 hours, rather than make it available all at once.

[Randy Holmes-Farley]

I'm not a fan of dosing sugar for several reasons, including the oxygen drop potential. I also don't have a dosage recommendation.

Do you have elevated nitrate and/or phosphate?

[michaeldaly]

Ok thanks guys. My tank does have a sump which adds some water to it's volume.

I am having a slight algae problem, and the sugar causes it to die off.

[Billybeau1]

Thats because the sugar is driving bacteria which is competing with phosphate for nutrients. This article may shed some light on your problem.

Phosphorus: Algae's best friend

http://www.advancedaquarist.com/issues/sept2002/chem.htm