--------------------------------------------------------------------------------

im getting fairly bad algae probs now even with 25% -50%water changes every week
the tanks been running brackish for about 3months now
currently has the stock internal filter which i have no idea of the turn over and an aqua1 cf1200 running along side it
any suggestions guys?

What lighting, and how long for?
Where is tank in relation to sunlight?
What are readings for nitrAte and phosphate?

i dont test for phos ( i guess i should be)
nitrAte never gets above 15 i guess , is normally stable at 10 between the weekly water changes
the tank dosnt get direct sunlight as such but does get about 2 hours of light cast on it near midday
as the the lights there is 4 tubes 2white which is on for 8hours then 1 red / 1 blue that is on 2 hours before and after and during the day totalling 12 hours

I think it would be worth testing for phosphate. My tap water is 5 ppm, so things are much better with rowaphos in the filter.
It is said to be helpful to have a siesta for the lighting - a couple of hours off in the middle of the day - it disrupts the algae's growth without upsetting other plants or fish.

Yeah test your tapwater and your tank water, the volume of water changes is irrelevent if your tapwater contains very high phosphate or nitrate, it wouldn't be helping the problem but feeding it.

That 2 hours of midday sun won't be helping, any way of blocking the light entering the tank?

yeah we have the blinds half shut during the day
it was the only place with no direct sunlight that the tank could go , perhaps i`ll adjust the timers for a break during the day
i have phos remover in my marine tank so i may bung some of that in there after ive tested it