A basic PH pen is ok but I treat them as a disposable aid as they dont seem to last or stay reliably for long.
I agree with
@foxfish all the way, I do have a Hanna pH pen wasn't cheap, but a cheap one will do the job, it doesn't even need to be accurate IMO as its the pH drop we are after not the actual pH of the water, can can also use pH test strips as some of them are pretty dare good
@X3NiTH or
@dw1305 will probably know of some good ones, its the fast result that counts, I cheap pH pen is much-much better than non - especially on your first go at CO
2 injection. DC are great for the colour change which is your main guide to [CO
2], but slow one of main takes about 3hrs so its poor of doing pH profiles but looks good on tank and great for telling me tank needs a trim-which is silly really as the plants sticking out of water does that also 😅
What happens with water changes? Surely this will impact things?
Yes, well spotted
, the tap water will have a higher [CO
2] than your 24hr water in glass, I have read that folks see better growth after WC day with fast growing plants. I did some casual experiments with CO
2 injection and did find that if the WC is close/next to CO
2 coming on the pre CO
2 time could be shorter than normal and still hit the same target pH. So I allow for this on WC day.
On my
500L tank I have duel CO2 injection and twin solenoids, twin CO2 reactors and a
PLC which does all the timing, I use to use a pH controller also ( pH controller is a waste of money IMO),
I have a crazy injection rate
Which gets ( or has got in pass) a 1.4pH drop in less than 30mins, use to shorten the pre CO2 on time 10mins if I had just done a WC.
Having a PLC does give industrial reliability with timers and just a completely different level of timing control - mainly thanks to
@ian_m with his LOGO!Soft Comfort programming he did with 'TankyMyTank' design, you adjust one time and it adjusts all on off times - its a work of art IMO. Only downside is PLCs are not cheap.
Once CO2 injection is mastered the need for a pH pen and pH profile isn't as great and many experienced scapers don't use them, but still a great tool IMO.
I also have a twinstar nano which allows me to see the full flow of water through the tank, so I can spot spots with less flow.
, agree 100% great for accessing flow, especially when using CO2 reactors