red algae in my 7 month old tank

Hi guys not sure why but all of a sudden I've started to get red algae growing on my sand.

I have live coral and fish
Tanks Tech specs are
Tank 300l
skimz sm 253 skimmer
2 sicce voyager 4 power heads.
1 sicce wave surfer.
1 syncra 2.5 return pump.
1 rensun 18 watt uv steriliser.
rensun sp 980 inlinne pump for uv filter.
Filter sock


Fish are as follows :-

2 Clowns
1 Yellow Tang
1 coral beauty
1 pyramid butterfly
1 box fish
1 blue belly fairy wrasse
1 6 stripe wrasse
1 moon light wrasse
1 sand sifting goby
1 fire goby
1 coral goby
Bubble-tip anemone

I do 30% water changes every two weeks
my levels are as follows
Salinity 1.240
PH 8.2
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate 2 ppm
KH 8.4 ppm
Magnesium 1300 ppm
calcium 410 ppm

I use sodium ascorbate every day to tackle the algae.
The lights were on only 8 hrs per day.
I've also tried keeping the lights off and this is not helping much.

i am at a loss any suggestions will be really appreciated.

 

Moved to Algae forum

 

pics of the algae

 

Algae

anyone ?

 

looks like cyano, kinda happens around this age of tank, IMO, I'd syphon it up as much as ya can. It should resolve itself soon. Are you using RODI water?

 

I buy my water from from a Marine aquarium shop and is R O water. just looks very unsightly.

 

you should invest in a ro/di unit you can get a real nice 75g per day unit for under 200. from bulk reef supply you dont know how offen the lfs changes there filters or what there tds readings are. canyo is from excess nutiants and lack of flow.

 

1 - ALWAYS make your own water. Frankly, I call everybody that sells things for money a liar until proven otherwise. For all you know, you're buying their old water after they pull a change.

2 - I think you're WAY overdoing it on your water changes. You're changing so much of it so often that your water probably never has a chance to be properly conditioned before you're getting rid of it.

You should only be doing 10% every two weeks or 20% monthly. 30% every two weeks is just way over the top. It probably doesn't have time to get filtered and conditioned properly by the time you're yanking it out again.

Ease up. You, in essence, are creating a new tank every two weeks. It's not necessary.

 

In the short term you can siphon the areas where the cyano is growing. In the long term you should look at possible causes of the cyano growth. There are some commercial dry foods also contain excess nutrients and other undesirable things like nitrates, phosphates etc so I strain/rinse my fresh/frozen foods before feeding my tank. You may want to consider feeding your fish less often. Also, changing your photo period, light bulbs, adding more flow, using RO/DI water. Adding a phosphate remover like TM Elimi-Phos and increasing flow in your tank may help too.

 

red algae

i am off to the boxing day sales and picking up a reactor and a chiller. will be also looking at turning up my return pump. Hopefully this will sort it but i will keep you all posted.

Thanks for all your help

And have a very merry christmas