Need help, sand turning brown

jandreau · Feb 14, 2015

I have a 2 year old 72 gal. aquarium that has had a brown film on the sand for about 4 months now. It seems to go away when the lights are off but within a half hour of the lights coming on it turns brown again. I have noticed all my nasarrius snails have died in the last few months. At first I thought it was my lights so I replaced my T5 HO 3-bulb Light Fixture with a 6-bulb fixture and new bulbs but it didn't help. I tried blacking out the aquarium for 3 days and it looked like it was gone but within 24 hrs. the sand was covered again. I added a GFO & Carbon Reactor about a week ago but haven't noticed a difference yet. I don't think I'm overfeeding I only feed them one Frozen Brine Shrimp cube a day. I was told that it might be Dinoflagellates and not to do water changes if it is. I haven't done a water change in two weeks but I noticed my ammonia is 0.25 now. I believe there is enough flow I have 2 Jebao WP-40's. any suggestions or help would be greatly appreciated.

I just did a water test and here is what I got back:
phosphates: 0.25
Ammonia: 0.25
Nitrites: 0
Nitrates: 0
pH: 7.8
Temp: 78
TDS reading on the Ro unit is 0

deerhunter06 · Feb 14, 2015

strange to have ammonia and no nitrates. im gonna say that's a test error probably Api test kit. do you use RO water? A picture of it would really help

redfishbluefish · Feb 14, 2015

Your phosphate number is too high. Need to run GFO or some other phosphate absorber.

And I agree, that ammonia on a two year old tank is a head scratcher.

jandreau · Feb 14, 2015

Yes it is a API test kit and I use RO water. Here is a few pictures

deerhunter06 · Feb 14, 2015

looks like diatoms which indicates something is wrong with you water chemistry, they are result of silicates in your water

deerhunter06 · Feb 14, 2015

what kind of sand did you use was it a silica sand?

jandreau · Feb 14, 2015

I used Nature's Ocean Bio-Activ Live Aragonite Reef Sand from petco.

deerhunter06 · Feb 14, 2015

I dunno then I don't know why u would be getting diatoms 2 years in maybe it's something else.

mayday610 · Feb 14, 2015

I had the same thing happen on my 150g that was running for over 5 years. unfortunately I never found the cause. The only thing that was different was the fact that I had a clown that decided one day to start "mining" in my DSB. I figured that it dug up some not so good stuff from under the rockwork even though I had no changes in test results. It never did take care of itself but I personally wasn't bothered by it. The fish were healthy, the corals all doing well, and that was good enough for me. I recently moved and broke down the tank. Since then I haven't had a problem. I moved all the livestock and used the same water and live rock. The only thing I changed was the lack of using the DSB. I took off the top two inches and I tossed the rest. So far so good, but time will tell

nhorner · Feb 15, 2015

Do water water changes every 4 days 25% for 1 month. It will disappear

nhorner · Feb 15, 2015

to much nutrients and/or phosphates

100LL · Feb 15, 2015

From what I've seen, it sounds like stereotypical Dino to me. As others mention, your water chemistry seems to need to be addressed, but if Dino I don't believe to two to be directly related.

DLuce510 · Feb 15, 2015

Don't think your phosphate is too high and I would say nitrate is too low. Some nutrients are good, too many is bad, listen to your tank and find what works well for your livestock.
Wouldn't worry about it too much, if your corals and fish look happy. Your sand is a low oxygen enviorment which things like that Brown film and cyanobacteria thrive in. If it's really bothering you, and sand siffting sea star or some sleeper goby's will move the sand around and give it oxygen.
Otherwise if your fish and corals are happy not a big deal.

wangspeed · Feb 16, 2015

If it disappears at lights out, it's likely dinoflagellates. Sorry. Better read up on them. I defeated them with peroxide and a blackout.

Sterlingg · Feb 16, 2015

I'd focus on the lighting more so as a pose to the water chemistry. Whites , reds , greens, etc encourages growth similar to yours. Perhaps blackout or only blue (lighting) + syphon waterchange of the sand bed may help target the concern. Hope it helps. Cheers.