Cycling the tank

[GoPhish]

My brand new tank ...120g with 40g sump. Atb 840 Skimmer. Refugium with miracle n mineral mud combined for a 1 inch layer. Also I have a batch of cheato in refugium but no light yet over refugium. I filled tanking using real ocean water n topped off the evaporation with tap water filtered through a Britta(i was desperate) Using Wave Point T5's. The tank has been cycling for about a week and already I have brown algae forming in DT. Mainly forming on sand in DT and primarily growing on mud that was dislodged from refugium and sprinkled across top layer of sand. The guy at LFS told me to not turn on lights during cycling so I've since shut them off. Also indirect sunlight is hitting the tank because we have no curtains, but it's very indirect. I don't want the brown algae becoming a problem that takes hold of the tank before it gets going. Suggestions

[Sugar Magnolia]

The diatoms are a normal part of the cycle and will recede over time. Nothing to worry about at all. Get yourself an RO/DI unit asap. The tap water, filtered through the Brita still contains trace amounts of minerals and chloramine which can cause issues with nuisance algaes in the future. If you can't get an RO/DI unit soon, use bottled distlled for top-off.

[HanoverFist]

Are you testing your water parameters? Should be testing ammonia, nitrites and nitrates during cycle.

Good idea to watch alk, ca and phosphates too if you have them. I ended up getting an alk test kit because it's crucial for maintaining pH. Now i'm planning on ca and phosphates test kits in near future.

[bertoni]

I agree that the brown film (which might be diatoms, but might not) likely will go away on its own. Does the tank have any live rock or other source of filtration?

[GoPhish]

30lbs of live rock so far but going to add another 45-60lbs. I'm on such a tight budget and used what I had to get a nice skimmer, tank, etc. Also 25lbs of live sand in DT but not enough to create a DSB.

[GoPhish]

Also I started using some Bottled water purified via R/O from Store for top off. Is Distilled better?

[GoPhish]

I have not tested yet. Still haven't purchased a test kit. I kind of figured that cycling is cycling and that I would give it 2 months and test before I added any fish/coral. At that point I'll have my next wave of cash saved up and can buy any extras including a test kit. There is a small anemone that came in on live rock that is still alive so I figure that's a good sign.

[bertoni]

Distilled might be significantly better, depending on how well the RO setup is maintained. I'd be tempted to use distilled.