Question regaring co2 and light...

[Samgoody]

I am currently using a 120w powercompact light and pressurzied co2 system in my 70gal. tank.

Plants are doing fine but I am thinking about switching to a 240w powercompact light so I can put some high light plants in my tank.

I don't know what the co2 concentration is my tank right now.

What i want to know is....If I switch to a 240w light then Do I also need to increase the input amount of co2? What will likely to happen if i don't increase the co2 level?

What test kit is good for testing ph and kh to find out the co2 level? Is Lamott any good?

Thanks!

[Milan]

With 3.4W/gal you will need a minimum of 30 ppm of dissolved CO2. Otherwise your plants will be CO2 limited, and the algae will take over it.

LaMotte test kit are excellent, but expensive too. However, AP or Hagen KH and PH kits, commonly found on the market would suffice. From KH and pH measured, you can calculate the CO2 concentration. Here is the info on this.

Also, you will have to increase the supply of other nutrients, such as N, P and K sufficiently to reflect the increased plants metabolism.

Edited December 13, 2005 by Milan

[Samgoody]

I am currently using Seacheam Florish and Florish Iron.

What else do I need?

Potassium, trace element...??

Thanks!

[Milan]

Seachem Florish is just traces, and perhaps some K. If you wish to stick with commercial ferts you will need Potassium, Nitrogen and Phosphorus, from their product line. This gets expensive for a high lights tank. However, the cheaper alternative are KNO3 (Potassium Nitrate), KH2PO4 (Mono Potassium Phosphate), which you can purchase at most hydroponic shops for considerable less money.

You mix them with water and make your own ferts and dose following recommendations already developed for these type of ferts. If you are interested in this, I can provide you with such information.