Algae Problems

[George Farmer]

I've got a Juwel Rio 125 stocked with softwater species, Blue and Gold Rams, Rummynose and Cardinal Tetras, Leopard Corys, Otos and a pair of Angels. It's also failrly well-planted (75% gravel covered). I'm using 100% RO water with remineralisers to reach desired gH and kH. My Nitrates and Phosphates are virtually 0 (can't get a reading using Nutrafin Liquid Test Kits) but I'm getting a constant build up of hair algae on my decor and Amazon Swords, I'm also getting a 'bright' green algae type layer covering patches of my gravel which builds up very quickly after repeatedely cleaning the affected areas. I've heard of blue-green algae which is actually bacterial rather than algae, could it be this and how can I combat it? I'm doing all the normal things to slow algae build-up, i.e turn off lights for a 'siesta', have fast growing plants, low aeration and algae eating fish, change 25% water weekly. Any ideas short of using an algaecide?

 

[wetwetwet]

Hi gf - the dreaded algae

Personally I don't mind small amounts - but if it becomes unsightly then it can get very frustrateing - I think everyone has a problem with it at some stage

It sounds like you're doing everything right... and you've obviously got little phosphate or nitrate because of the RO (unless either of these are added back in?)

What is the actuall lighting period and is there any direct sunlight?

 

[George Farmer]

The lights come on for 5 hours, then off for 2, then on for 5. There's very little natural light, only from a partially open blind 90 degrees to the tank. I think the bright green algae may be blue-green slime algae after a bit of research. I've removed a load of gravel from the tank and cleaned it thouroughly hopefully killing the bacteria.

 

[Dragonslair]

If I had a penny every time someone asked about the dreaded algae, I would be an extremely rich man by now. Personally I think you are giving too much light. I see what you are saying when you say that you turn off the lighting for 2 hours. Remember even when the lighting is off, the "captured" light rom the window is still projecting to your tank. The tank is not in absolute blackness, like it would be during the night. Therefore you are still subjecting the tank to 12 hours of light a day. No wonder you have algae problems. The bad news is once hair algae takes hold the only way to rid it is to physically scrub it off everything, discard plant leaves and to scrub an algaecide into the decor, and then give it all a through rinsing before returning it back to the tank. The next thing is to drastically reduce the lighting to a total of 5 hours a day in total, and then work up from there if you wish. I would advise against having more than 8 hours in total per day.
The tank should smell foul if the culprit is blue-green algae. If it is I suggest you disinfect the whole tank down. This type of algae excretes toxins deadly to all fish life. It smells really foul and is very slimey to pick up.(Nose wrinkling)