Wrongturn- 
..yeah, the pH thing can make your frontal lobe collapse if you're not familiar with the water chemistry basics behind pH, buffering, water hardness, etc.,... :slaps: .... here's some good info about all this,...I hear you about the costs, but they will pay for themselves in short order when you consider things,... and prevention of FUBAR grow errors will save your sanity as well!...
> the very best, most accurate and efficient way to deal with managing the pH of your water, nute' solutions, and soil is with a pH meter that tests liquids, and that Accurate 8 soil pH probe, for reading actual soil pH
in the pot-- nothing beats this for relevance!... I strongly dislike the run-off method because there are way to many sources of potential measurement error in that method,.. it'll do in a pinch, if done spot-on right, otherwise, the readings cannot be trusted... and when your plants are really on the line, rough estimates of pH don't cut it,... nutrient availability, lockout ranges, and corrections may come down to tenths (0.1) differences often,... The problem with color type testers is with the nute' solutions/run-off being colored themselves, which will screw the accuracy right off the bat,... As a aquarium owner, I assume you know enough about water sources, RO/DI vs. tap, hardness, buffering and all that..? (LOL!- also, another meter that's invaluable is an EC or TDS meter, --TDS's can be had for about $20),... Anyway, keeping the soil pH in proper range starts with dialing in your inputs,.. most nute' solutions are acidic, but the water you dissolve them in (hardness) makes a profound difference in stability of the pH, and how readily it can be adjusted,... I'm sure you get it bro', just making the case for you to invest when you can, and be super careful when working/measuring pH's with methods and test gear that's prone to error,... BTW, WG's soils mix needs more lime,... several folks have complained about high acidity,... and keep in mind, how variably sensitive auto seedling are to nutrients,....