Can do with some advice

[BenA]

My 110gl tank has a problem that I can't solve, this have started about 2 weeks ago.

The tank was cycle for about 7 weeks before plants and fish were introduced around 3/6/. I had all sorts of algae and fungi growing, they all have gone, some with the help of the 4 Ottos. Currently there is no brown algae and very little Green Spot Algae on the glass and some plants. However, all the plants are covered with what I can only describe as 'brown dust'. The water is cloudy and many small particles can be seen. If I gently shake the plants or the roots of the floating plants then the water fills with debris that slowly sink or get pulled in by the filter. There are no rotting or melting plants. I use NTL Light fertilizer for the floating plants, the Anubias Java Moss etc. The rooted plants are planted in a substrate made by Tropica. 

The fish inside are:

Cories (Sterbi/Adolpo) - 12

White/Gold Cloud Minnoows - 14

Emperror Tetra - 8

Hengeli Rasbora - 8

Celebes Rainbow - 8

Threadfin Rainbow -  6

Ottos - 4

Last weekend I have tested the water (X2 as all seemed strange) results were:

Ammonia, Nitrite, Nitrate and Phosphate - 0ppm

PH - 7.5 - 8.0

Temp. - 75F (24C)

Every 2 weeks I change 30gl. of water and syphon the sand and gravel.

Any ideas?

Thanks

Edited April 22, 2021 by BenA

[H.K.Luterman]

Sounds like diatoms. They're part of the "settling in" process, showing up within the first few months of a new tank, and are caused by excess silicates. Once the silicates dwindle, the diatoms will clear up. It's more or less a waiting game, though snails will happily eat them.  In the mean time you can help your plants by brushing it off their leaves with your fingers. 

[KBOzzie59]

21 minutes ago, BenA said:

The tank was cycle for about 7 weeks

Did the cycle actually finish?  0 Nitrates tells me it did not.

[CT_]

20 minutes ago, KBOzzie59 said:

Did the cycle actually finish?  0 Nitrates tells me it did not.

Tests showed 0 nitrogen and 0 phosphate + ferts and healthily plants makes me dubious.  I'd double check your tests are working right.  Try testing your tap and also testing tap+dilute ferts.  Also with 4 otos the diatoms should be gone in a day.

[Mmiller2001]

Most likely, your tank is under filtered. Increase the turnover and improve flow throughout the tank.

Edited April 22, 2021 by Mmiller2001

[Patrick_G]

In addition to the above advice I’d also make sure you’re shaking up that Nitrate test bottle and following the directions exactly. It’s easy to get a false reading. I’m pointing to myself! 🤫

Edited April 23, 2021 by Patrick_G

[BenA]

Thank you all.

Yes, the tank is fully cycled as it is the first time for me to have '0' Nitrate. I have introduced lots of floating plants to reduce it from ~ 80ppm.

I don't think that this brown 'dust' is diatoms, in order to make it go into the water flow all I have to do is just to move the moss or any other plant very gently and it is all over, no need to rub. It looks more like organic material than anything else, but if diatoms can be removed this way then this is the answer. As for filtration I have the Oase 850 external filter that provides 1500ltr/h flow. The jets were very powerful so I have drilled another 2 holes into the spray bar and slightly increased the rest, effectively reducing the pressure while keeping the flow rate. Last week I opened the filter to check the sponges which were fairly clean. Thanks for the tip about shaking the Nitrate tester, didn't do it. I also made a mistake with the fertilizer brand's name, can't be NTL 🙄, it is TNC. 

Tomorrow I plan to give the tank a good clean, get rid of all the Java moss and change ~ 30gl of water. 

Thanks again.