Are there any other ways of determining co2 in a tank other than using the ph/kh chart.

I am using Seachem Onyx for my tanks and I read in their website that Onyx tend to lower ph by 0.1-0.5. So that would screwed the measurement if I use the chart meathod.

I tried the meathod that was posted in this thread http://www.aquaticquotient.com/forum...o2+measurement and the measurement I've got is way more than 30ppm of co2 in my tank. Plants and fishes are doing okay but I've still got BBA appearing here and there and I've ruled out water circulation. I'm pumping like 2.5 bps for my 10 gallon tank via a reactor and pearling starts 2 hours into photoperiod but BBA is still appearing.

Below are my tank parameters
Tank Dimensions (LxWxH, specify units):36cmx36cmx29cm

Lighting Intensity(No of Watts) :24watt
Number and type of Lighting (FL/PL/MH) :PL
Age of light bulbs :1 month
No. of hours your lights are on :10hrs

CO2 Injection Rate (bps) :2.5
Type of CO2 (DIY/Cylinder) :Cylinder
Method of Injection (e.g. Diffusor/Reactor) :Reactor

Liquid fertilisers Used (Product name. E.g. Seachem Flourish) :Flourish
Fertilization regime (Frequency and amount per dose) :EI Meathod, KNO3 and KH2PO4. 50%weekly water change and 1/8 teaspoon of Equilibrium.

Other fertilisers (Product name. E.g. Root Monster) :

Other additives (Product name. E.g. Seachem Prime) :Prime

Type of Filter (overhead/internal/canister, Product name/model if possible) :Canister
When was the filter last washed : 1 week ago
Filter media used : Sponge, ceramic rings, bioballs and biohome
When was the media last changed :
What was changed :

Age of setup (i.e. since initial setup or last major re-do ) : 1.5 mnths

Water change frequency :weekly
Amount changed :50%

Water surface movement (None/gentle/turbulent) : Gentle
Circulation (None/gentle/turbulent) :Gentle

Tank Temperature :28

Chemical Properties (Fill what you can)
-------------------------------------
KH (dKH): 8
GH (dGH)?
pH :6.8
NH4 (ppm)?
NO2 (ppm)?
NO3 (ppm): ??
PO4 (ppm)?
Fe (ppm)?

Bioload (Number and type of fish and plants)
------------------------------------------
Fish: 4 white cloud minnows, 4 pencilfish, 1 swordtail and 1 oto
Plants : HM, Blyxa Japonica, Glosso and 2 unknown plants.