Algae Issues

Hi all

Like many a fishkeeper will experience, I'm currently having an algae-based headache.  My plastic rocks are absolutely covered, and although I can live with some, this does look quite unsightly. 

The tank has been running for about a year now and the algae has gradually increased rather than a sudden spike.  I have previously cleaned the rock manually - although when I did this it was taking the rock right back to its base plastic (did not look good).  My Bristlenose & SAE completely stripped the rock when they first arrived but the algae grew back worse and greener than before and now they don't seem too interested.




Here's my stock list:


My nitrates are 40ppm out of the tap and don't tend to go much higher than that.  I do a weekly PWC of about 35L.
I did also test the water for phosphate and that was coming out quite high. Lights are on from 8-12 in the morning and then 5-10 in the evening.  Total of 9 hours.  I previously fed flake in the morning and frozen in the evening but have cut that down to a smaller amount of flake in the morning only for the past 2 weeks to no avail.

I have been considering whether the tap water could be the main source of the problem.  I also have a 30l marine nano, which of course uses RO water.  So I've been thinking about whether to start using RO on the trop tank to try and combat the algae issues.

Any ideas folks?

You're spot on about the plants Sue.  Java fern & anubias to my knowledge.  Also have a couple of moss balls in there but I believe they're fairly low light too. 

I've had the same experience with keeping other plants - they tend to go rather brown!

Thanks Colin - do you add any trace elements in to your water or is the 2parts tap enough to keep things healthy?

Whether to add anything to an RO/tap mix will depend on just how much tap water is in the mix, and how hard that tap water is.
If the tap water is very soft and you use RO because of the nitrate in it, you could end up with so few minerals that the fish can't cope. But using hard water to mix with RO wouldn't cause a problem, unless the tank had something like Rift Lake cichlids in it.
And mixing RO with tap water with low carbonate levels (KH) would put the tank at risk of a pH crash if minerals were not added back.


It is possible to have soft water with high nitrate. Soft just means the water doesn't have much calcium or magnesium.