Re: Roseman's Deep Water Culture Tutorial, SH Kit & DIY
pH
The pH should not vary more than .5 to .7 everyday, but it will vary that much from just absorbing nutes, and if it does flucuate alot more up OR down daily, something is wrong.
First, ask yourself, IF growing in HYDRO, what is going into the reservoir tank? Water, Nutes, pH UP and Down should be it. Adding anything else, WHEN YOU DO NOT HAVE A PROBLEM, is not the wisest thing to do. (Yes, sometimes some small amount of peroxide or hydrozyme might be needed, but I've done 7 grows without it.)
And if you are making NUTE SOUP, ( a nute mix and supplement mix of more than two nutrients) I can not help you or advise you about your pH.
Except for the very first time you add the water to the tank, You should pH balance your water FIRST, everytime, outside of the tank, then add the nutes, pH balance it again, then add it to the tank. Rule of thumb is your pH should not go up more than .5 within one 12 hour day or 1.0 in 24 hours.
If it does go up more in one day or two days, you got to do something to stabilize it. After the first two or 3 weeks pass, and the plants are drinking a gallon a day, you can add one gallon back that is over adjusted or over compensated, to get it back down. FOR EXAMPLE, If the tank is reading 7.2, then add one gallon of 6.2, and you'll get it down SOME, without it being too drastic.
DRASTIC pH CHANGES WITHIN 24 HOURS ARE VERY DANGEROUS.
QUICK FIXES:
IF YOU ARE HAVING A PROBLEM, AND ONLY IF IT IS GOING UP AND DOWN WILDLY, then try adding a lump of charcoal or two, tied inside a panty hose or nylon stocking to the tank.
OR
Go to Walmart or PetSmart to the Aquarium Dept, next to the fish food, filters and additives and sea salts, and get those little packages of Ammonia Control Absorbent Packets. They look like little sponges in a wrapper. They work great to stabilize the pH. Or get the Ammonia control packets and add a couple to the tank.
IF YOU ARE HAVING A PROBLEM, AND ONLY IF IT IS GOING UP AND DOWN WILDLY, and you need a remedy ASAP then get everything in your tank like you want it, (except the roots or plants,) and add two heaping tablespoons of baking soda to a gallon of water, stir it good, then add it to the tank. THIS WILL RAISE IT TOO HIGH but will stop the drastic Flucuations. Wait ten minutes, then pH adjust it DOWN again. Then it should stay stabilized until the next Drain and Replenish.
QUICK FIXES should be avoided and be the very last resort. QUICK FIXES should be a TEMPORARY Fix, until you can do the right and proper FIX.
Do not use the charcoal, or buffers if you do not have to have them. They are only to be used in extreme flucuations and only for a Quick Fix for a day.
From the book:
A buffer solution is an aqueous solution consisting of a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. It has the property that the pH of the solution changes very little when a small amount of acid or base is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications.