Struggling with new marine set-up..

[bigfatfish]

Recently upped my SG from BW to marine. Started with brown algae/diatom issue & realised I had high phosphates in my tap water - I used a phosphate remover & started using RO water. I still have issues with the horrible brown stuff, although to a lesser degree.
Now I am struggling to keep the water temp below 26. I have turned the heater off in case there was a problem with that, but the temp has remained high (I have a stick on thermometer/a normal glass one & a digital one & they all say the same).. My house thermostart is set at 18.
I have a 55Uk gallon tank, with 10 gallon sump. I have a 2 pumps in the sump - one for the skimmer & one for water return. In the tank there are 2 powerheads & a small fluval internal filter that I am running until complete switch over to the liverock once the tank is stable. There is about 20kg LR at the moment & 20kg baserock. The lights are 2 x T5 marine lights (which came with the tank & were used when it was BW with no probs with excess heat) & 2 blue lights for evening viewing.
My ammonia/nitrite/phosphate are zero & my nitrate is just about registering on the colour scale, so <5.
So, I have a hot, brown tank!! Where am I going wrong? The algae, I can wait out, but the temp issue needs to be resolved.
Starting to wish i had not bothered to cross over to the dark side & stayed with BW!!

[greenspottedlover]

not sure try dropping bottle full of frozen water in tank to bring down temp. If you try this though, be SURE you don't drop it to much.

[Blaine]

You need to find out what is raising the temp. Adding ice will only bring the temperature down temporarily if you don't find out.

How high off the tank are your lights? Too close to the water without enough ventilation can raise the temp.

Check your pumps for heat. If they are older they can produce alot of heat in the sump and/or skimmer. Same with the internal filter and powerheads.

[bigfatfish]

Yeah, there is little point lowering the temp artificially, if I can't keep it there.

My pumps/powerheads/skimmer are all new. The only older thing is the internal filter - it doesn't feel warm to touch & i cleaned it all out thoroughly, in case there was something clogging it. None of the other electrical items are even warm to touch & appear to be working as they should. The lights? They do seem to kick out alot of heat, but they are not new to the tank, so why should that suddenly change? I have turned them off anyway, to see if it makes a difference over the next few hours. The heater has now been off for several hours & the temp has still not chnaged, so it isn't that. I will just have to switch things off one by one & wait.
Does anyone know what temps GSPs can tolerate? Currently at 25.9

[sevenyearnight]

Just did the conversion, that is the temp of my gsp's tanks normally. My room temp is just a couple degrees below that. 76° -78° f, and my room temp is about 74-75°F. What temp were you shooting for, or what was it before? Above 82° F might be uncomfortable for longer periods, but I know elevated temps are recommended as part of some disease remedies.
However, it is curious that the temp would have elevated for an unknown reason.

[bigfatfish]

I normally run at 24C, which is 75.2F

So, I guess I am ok for the moment at 25.9/78.6, but I have no heater on & would really like to know what is causing the heat!?

[Honeybadger]

It's probably one of the new pumps. Try turning one off for a day and see what happens. Then try another one another day.

[greenspottedlover]

as long as it does not go higher I'd say 78.6F is fine. My GSP tank stays at fairly steady 76F.

[bigfatfish]

I think I will have to do that, but I am nervous about fiddling around with too much, as it is a new set-up & I wanted everything to settle (I already had probs with ammonia during the switch over).
Guess I am going to have to bite the bullet!

[Honeybadger]

Which pumps are they? i had one of the cheapy sunsun ones that used to heat my reef.

[Pufferpunk]

26 is the temp you want.

[bigfatfish]

26 is the temp you want.

Really? I thought 24 was the ideal?

Anyway, I think I have isolated the problem overnight. I switched off the left side powerhead & the temp has dropped to 24. I will switch it on again today & see if the temp rises again.

[Honeybadger]

25 is what you need to aim for in a reef. Look at ATC 800 or TC-10 Temp controllers. Worth having!

[Pufferpunk]

Flow is extremely important in a reef. More important than light even. Do you have fans on your lights? I repeat: 26 is a fine temp for a reef.

[Honeybadger]

I repeat: 26 is a fine temp for a reef.

Until summer comes and it heats the tank too much. If you keep it a degree lower you have a little wiggle room.

Flow is very important but is worth knowing which pump is heating the water.