BBA is killing me instead of otherwise

[YDE]

First of all apologies for my weak english.

After a nearly 19-month battle against BBA, I'm really desperate and I don't know what to do anymore.

I have a Jewel Rio 350 tank with 2 external filters, a EHEIM professionel 5e 700 (flowrate 1850 l) and a EHEIM professionel 4+ 600 (flowrate 1250 l).

On the right side of the tank is the outflow from the Eheim 5e at the back with a lily-pipe directed in the length of the aquarium, and on the left side of the tank the Eheim 4 is equipped with a spray bar, the rear 2/3 of the spraybar pointing downwards against the side window, and the front 1/3 pointing just below the water surface to the other side of the aquarium

I dose CO2 with a JBL PROFLORA m2003 set with PH-controler, and the C2 is injected on both sides of the tank by 2 inline atomizers.

The CO2-mist is really everywhere in the aquarium.

I dose estimative index and the waterparameters at the end of the week before the weekly waterchange (60 %) are:

KH: 5

GH: 8

NH4: 0

NO2: 0.01

NO3: 25

PO4: ±2.3

K: 30

Fe: 0.6

Mg: 8

CO2: 6.6

I have tried everything to beat the BBA, spot-dosing liquid-carbon or hydrogen peroxide, pooring the right amount of liquid-carbon or hydrogen peroxide directly in the tank, reduced light intensity and duration of illumination, increased te CO2 ….

The tank is now illuminated for 8 hours of which 4 at 70%, the other 4 at 50% within a sunrise and sunset of 1 hour each time.

Is there anything i'm overlooking or does anyone know what else i can do?

Thanks in advance

 

[Allwissend]

One thing that comes up is the 6.6 CO2 ??? That is a very low and exact measurement for CO2. Maybe increasing CO2 should be one place to look into to improve the health of the plants plants.

Then it would perhaps be good to mention the kind of animals you have in that tanks which require such high filtration and maybe substrate and decorations. Red algae are often associated with organic material in my experience . Detritus below the wood or a rotting wood , or damaged plants will make a good growth medium for it

 

[Zeus]

A Full tank shot would help. Trouble with a pH controller is the pH fluctuates between the upper and lower limits of the pH controller. I have used one in the past and not a fan at all. Better to do a pH profile and get a stable pH from lights on till CO2 off.
The only thing I use the pH controller for is taking the pH, Plus with the aid of a PLC and a bit of wiring and programming the PLC records how long it takes to reach target pH which is handy.

How regular are you cleaning the filter and vacuuming/turkey blasting the substrate? helps keep on top of the detritus build up and on top of the DOCs ( Dissolved Organic Compounds) which have been reported to help control BBA from some folk.

I would increase the WC to at least 50% or two a week.

The use of liquid-carbon or hydrogen peroxide on a regular basis is crisis management which clearly isn't working.

Flow in tank which is king seems to play a big factor as well, Pic would help access flow rate/ spray bar setup, do plants sway?

What Media do you have in your filters, ceramic media and filter floss are real output killers esp if stuffed with ceramic. I use course and medium sponges and a handful of ceramic and regular cleaning to keep output optimum

DC (Drop Checker) colour change