First thing you need to do is get a good meter. If you dont have one, it's flying blind. Even if you go DWC, you still need to know what your PH is. I wouldn't even invest in a DWC system till you have a good meter. The one you have there is still not accurate. I've gone through 10 of those things... they are always off compared to a good pen/meter... like the old saying "You get what you pay for" It's like doing heart surgery with a Cresent wrench.
Amazon.com: Oakton OK35423-00 Waterproof pH1 EcoTster Solution Meters & Solutions, White: Industrial & Scientific
Amazon.com: Oakton OK35423-00 Waterproof pH1 EcoTster Solution Meters & Solutions, White: Industrial & Scientific
www.amazon.com
or which do you reocmmend?