Tank Setups • cloudy water issue

[Iggy Newcastle]

This is my first major issue with my 1st tank. 125 gallon, PFS, mostly granite rocks- up and running for just over a month and cycled using Dr Tim's One and Only. Stock is all mbuna, totaling 42 fish ranging from 1.5-2.5" Lighting is 2) 10000k coralife 35w bulbs. Ammo-0, Nitrite- 0, Nitrates- 5 to 10ppm(have never tested over 15 or so. I do weekly water changes ranging from 30-70%(the latter being the most, after the tank cycled). The lighting was a bit excessive at 12 hrs a day. Filtration is 5.6 x and hour. Tank has always been crystal clear. I hope that covers everything.

After reading countless posts on cloudy water, I have not found one that matches my issue. 4 days ago, I noticed my water a bit cloudy. The following day, after the lights turned on, it was much better. I left the house for a few hours. When I returned, the cloudiness had returned. I killed the lights. The following morning the tank was much better, but once again after the lights were on for awhile, it clouded up again. I did a 50% water change. The cloudiness returned within an hour. I killed the lights, again. The next morning the tank looked great. Not crystal clear, but very clear. I decided to keep going with my 'experiment' and turned the lights on in the afternoon. A few hours later the cloudiness returned. I shut down the lighting. This morning the tank was the clearest it has been since this started. Currently the lights are off. I did all these 'tests' in anticipation of posting my issue.

I have fed only twice since this began. I never feed more than can be consumed within 30 seconds, maybe a minute or so when using flakes. A couple weeks ago, brown algae started to show on rocks and top of the sand. I expected this. Also, some green algae appeared on a rock closest to my lighting, and hasn't spread nearly as fast as the brown. When I did my last WC, I scrubbed off the majority of the brown from the rocks. I actually didn't mind the algae. Thought it looked natural. I filled up a white coffee mug with tank water. It doesn't look green. When looking through the length of the tank, it kinda looks like a mix of green/white.

Is it possible I have caught an algae bloom early? I don't think it has to do with bacteria, only because it appears to become cloudy when the lighting has been on for a few hours. The tank does get some natural sunlight, but rarely, as I close the blinds leading out to the deck through the sliding glass door. Someone just has the tendency to leave them open . Plans for the near future include a new canister(fx5) to up my filtration, as I do believe it's too low. If it is an algae bloom, I would get a UV sterilizer.

I know this post was lengthy, but figured I would include everything I could think of. Thanks for reading. I'd appreciate any input or suggestions.

[AulonoKarl]

Did you rinse, rinse, rinse, and then rinse again before you added your sand? Your fish are going to be more active when the lights are on and it could be that they are sifting through the sand when the lights are on and it's clouding the water.

[Iggy Newcastle]

Good point. Sand was rinsed and rinsed and rinsed. Stocking went like this- added 6, added 5, added 4, added 12, removed 4(hybrids), added 21(from an online source). No cloudiness for 13 days after stocking was complete.

I don't think its dirty sand from the fish sifting through it.

[countryboy814]

It sounds like it could be bacterial. What type of filters are you using?

[AulonoKarl]

Could be a diatom bloom. It's common for newly setup tanks, especially when sand is used, as they feed on silicates in the water. If that's what it is, the best solution is to stay on top of water changes, and wait. The silicate levels in the water from the sand will drop off before too long.

[countryboy814]

Could be over stocking. 42 fish is a load for 125 gal.

[Iggy Newcastle]

Thanks for the replies. I realize that 42 fish is overstocking, but they are mbuna. And since the majority are sexually immature, I will have to remove a few as things progress.

If it is an algae bloom, and it doesn't correct itself over time and water changes, would a UV sterilizer solve future blooms? I know they're expensive, but I hate the cloudiness.

[countryboy814]

UV generally only takes care of green free floating algae. I'm still not convinced that they work. I have one on my canister beause it came with one.

[AulonoKarl]

Regular algae blooms can be solved by limiting the light and nitrates in the water. Diatoms (a type of algae as well), you just kind of have to let them run their course. I've had this happen both times I've added sand to tanks. It wasn't a real bad cloudiness, but just a light haze.

[Iggy Newcastle]

Regular algae blooms can be solved by limiting the light and nitrates in the water. Diatoms (a type of algae as well), you just kind of have to let them run their course. I've had this happen both times I've added sand to tanks. It wasn't a real bad cloudiness, but just a light haze.

Ok. I would say that my cloud was light as well. I've been on top of water tests and changes since I started up. I noticed it right away. Researching algae early on, I learned about brown diatoms. I figured they'd show up. Just never read anything about a diatom bloom. I'm stumped on why it only shows up after the lights have been on for awhile. I'll take the WC and lighting advice and see what happens. Thought I'd ask the forum before it gets out of control. Thanks.

[Iggy Newcastle]

UV generally only takes care of green free floating algae. I'm still not convinced that they work. I have one on my canister beause it came with one.

Thanks. I'll hold off on any UV, since I don't have a for sure green, free floating bloom.