Help!? Unkown Purple film found on bottom of 7gal. mini reef

[astrong]

Usually its a sign of low pH, low KH, low flow or high organics. Or any combination in between.

Have you water tested. Chemi-clean is an excellent product but if your chemistry is off, the slime will be back. Cyanobacteria is a single celled colonial photosynthetic bacteria that clumps in low flow areas. It likes water with high CO2 and low pH. So change that and it tends to go away on its own. And if it doesn't, hit it with Chemi-clean, turn off your skimmer, wait 48 hours and do a 20% water change. Usually very effective.

Also, Cyano itself is not detrimental, but it usually indicateds something is off.

[marinebeginner]

Thank you! What is KH. I do think the flow may be a little low. What would be an example of high organics? Like waste, too much feeding or overloaded tank? What are some ways to increase my flow?

[marinebeginner]

Checked my ph to day and it was perfect. However the salinity was very high as was the ca+
I added water and will do a 20% change on sat.

[MikeDeL]

What exactly were the test readings? That will help the chemistry buffs help you out. Also be sure you top off the tank DAILY. Salinity swings quickly in nanos. I usually top mine off every afternoon at feeding time.
KH is the measure of the buffer in your tank. The buffer stabalizes you ph. Organics come from food and fish waste. If your nitrates are high you could be feeding too much, have too much live stock, not enough filtration, or a combination of any of these.
To increase flow just get yourself a small powerhead to stick in there. You could position it so that the current of one power head crosses the current of the other, or have one shooting from back to front and one shooting from side to side also. Just make sure there arent too many dead spots, where the water doesnt circulate alot.

[MikeDeL]

Also when you do your water change try to syphon off as much of the cyano as possible.

[marinebeginner]

Thank you!!! Alright, the ph was 8.2-8.4, ca 1600(yikes) I might have messed up or something! Specific gravity was like-1.030 I think-higher then the normal rang of I think 1.020. So, I added about 1/2 gallon of rho h2o and a little less then a scoop of chemi-clean. I scooped out as much of the cynobacteria I could get and pulled out the little chunk of spider algae. I then added hermit crabs. However, it looked like one was eating the coral!!! While I was messing around I bumped the corals! Also, there is this wierd deep purple-amithyst color looking thing between our green mushrooms. It looks like a tangled up piece of fishing wire or a hair ball or something. Good or bad? Kind of pretty.
Looks a little like spiral bacteria does under a microscope.
Anyway, fish seem fabulous as does the cleaner shrimp. Coral looks very healthy too.

[GaryP]

I don't think its possible to get your calcium to 1600. Please check it again. I don't know of a kit that will even measure levels that high. Salinity should be around 1.023-.026. Be careful to not add a large amount of RO water at one time. You want your salinity to change fairly slowly. What kind of hermit crabs did you add? They don't typically eat corals. It might have been eating some algae or detritus near or caught in the coral. I have no idea what the amethyst colored stuff is without a pic. Except for the color it sounds like chaetamorpha macroalgae. You probably need to get an alkalinity kit and check that too.

Gary