<a href=showthread.php?s=&postid=11449205#post11449205 target=_blank>Originally posted</a> by PSam
The optim / digest should eventually drop / keep PO4 down. I took off GFO and haven't seen any need to put it back.
What's your current PO4 level?
<a href=showthread.php?s=&postid=11449587#post11449587 target=_blank>Originally posted</a> by reefkoi
A hanna phos meter is very accurate, maybe someone in your area has one. I finally broke down and bought one and its very easy to use and accutrate!
C
<a href=showthread.php?s=&postid=11449610#post11449610 target=_blank>Originally posted</a> by Primetime33
Zedar,
I looked at the above kits and they seem to be real good kits. I have a question about the tropic marine kit, how can it be so cheap and still be as good as the Hach or the Merck? Or is the Tropic Marin similar to the API in terms of reliability/accuracy?