Algae!

[BlueWorldJeff]

I've been battling algae on my sand bed and rocks since i think my tank went through a mini-cycle about 2 months ago when I was vacuuming my sand bed during water changes. I do water changes every other week and do about 30 gallons and now, just vacuum the algae off the surface of the sandbed. My tank is 180 + 30 for sump. Looks like cyano, diatoms and everything else that could grow, is

Please don't mind the dirty glass, haven't cleaned it this week. This is from about 2 weeks without a water change:

I've also been chasing better water parameters as well. I want to get my Alk down under 8 to about 7.5-8 and get my calcium up to 420 and magnesium around 1350+.

I've dropped my alk dosing and my alk now registers about 7.7, but I havent been able to raise my calcium or magnesium. They stay at 370 and 1200 respectively. I have been raising the drip on the calcium as well as dumping cups of calcium 2 part and magnesium 2 part in at a time.

Could the algae be related to the low calcium and magnesium? I keep my phosphates under .10, closer to 0.0-0.4 and nitrates stay at 2 ppm.

 

[mtraylor]

Couple questions. Do you use filtered water to make your saltwater, or do you use freshwater? If you buy from a store I would check there TDS to see what its saying. If you use your own, what is your TDS reading. Swings in alkalinity would be my first guess at the algae. Your phosphates seem to be good. If I were you. I would stop all the dosing everything and concentrate on a couple big water changes and stabilize the tank. The monti's seem really light color which says alk. to me. Get a second reading on your alk.

 

[BlueWorldJeff]

thank you for the reply. I make my own RODI and just changed the DI resin. I have. TDS meter that reads zero in my top off and water change water. my Alk was high, like 9 and I turned down the dosing and it's at 7.7. I am trying to stabilize it now. Do you mean like 50% water changes? then how long after that to see where everything sits?