hi callisto168,

I believe yours is ISTA external CO2 diffuser. Yes 88Marine selling it for RM55. But got mine cheaper from somwehere else. Mine connected to a spraybar under waterline. You can connect it to in-tank type CO2 diffuser with rotation balls in it, to get almost 100% CO2 diffused. I know 88Marine in SunwayMas are using this, but they are also using Eheim Pro 3.

About the ADA process, I am no expert, you don't have to follow exactly, as every tank is different from others (plant mass, biomass, water quality etc). But since you only dosing Brighty K, you only get K. Plant needs micro nutrients too. That is why I suggested you to dose some trace elements. Using Brighty Step 1 seems appropriate in your case, and a lot easier since you have to dose X ml for Y liters, not like some other brand of trace elements. Anyway, the dosing instruction also can be different. You can see it here http://www.adaeuro.com/gestioneacquari_eng.asp . This is quite different from the dosing instruction that comes with the bottles.

If you are using ADA substrate, yes there are some nutrients in it, NO3 mostly. But since your tank is quite new, the plants does not establish the roots yet, this is quite small amount compared to water colum dosing, IMHO.

Anyway, is your tank is heavily planted?. If not, you may have to cut down the ferts. Don't want to waste your money, and have algae problems.

Best Regards

Thanks