Fungus on top of rapid rooter?

[konepure]

Hello.

I do DWC hydroponics and use hydroponics trio, Calmagic and Hydroguard.

The water temperature is maintained between 18 and 20 degrees Celsius using a cooling system.

The white foreign body on the top of the Rapid Rooter looks like a fungus, is that correct?

It seems that the top part is moist and mold is growing.

Pouring water from the tank on top seems to have some effect with HydroGuard, but it doesn't solve the root rot.

Root rot continues to occur and the cause is unknown.

[DW2]

Howdy konepure, I had a similar problem when I first started growing in a hydroponic system, only it was algae growing on the rockwool cubes and root rot. The temperatures, that You are maintaining should be OK. Are You keeping the water well aerated? I use four 6 inch by 2 inch air stones in each of my six gallon reservoirs. I also cover the top of the net pots with aluminum foil to block out the light leaks. The aluminum foil is 'soft' enough to allow the stems to grow with out needing to trim them and it does not constrict the stem at all.
Good luck with Your grow.

[konepure]

Thank you for answer.
You use air stone a lot. I am using two. It's not in the picture, but I'm also using aluminum foil.