Hey, everybody, kinda new to this but LOVING it. What a fascinating process. Have read comments on how addicting it can be, and I have to agree.
I have been interested in aquaponics for a few years now but never really did anything with it. Of course, at that time, I was looking at all the big systems with IBC's and "barrel ponics". If I had greenhouse or some such, would have gone there. Thinking about adding greenhouse to my pole barn though.
Any how, have had small aquarium (neglected) for about a year and over the past few months have been flushing fish down the commode so a few weeks ago decided to clean the tank and gosh, what a mess...
Using cheap five-in-one test strips I started with:
Nitrates: @ 160
Nitrites: @ 2.5
Hardness: @ 300
Alkaline: @ 60
pH: @ 7.2
My latest test on 1/21/15 gives me:
Nitrate: @ 100 ( still high)
Nitrite: @ 2.5
Hardness: Still 300
Alkaline: @ 0
pH: @ midway between 6.2 and 6.8
Now, a day or two before I had to remove the grow media to install a taller media guard, so I am thinking maybe disturbing the media may have something to do with pH drop? Am monitoring it for a few more days and see what happens. Might consider adding some bio-char to raise pH. Thoughts? I haven't read of anyone trying this.
Never heard of using bio-char to raise Ph but that doesn't mean it won't work. Baking soda or Red Devil Lye(Sodium Hydroxide) will raise Ph. You should invest in the API master test kit and get ammonia readings as well. BTW 6.2-6.8 is good Ph for plants and fish together.
You really don't want to use NaOH (Sodium Hydroxide) to raise pH. If hydroxides are to be your choice base...then Potassium Hydroxide (also called "lye", so it gets confusing) would be the way to go...
on your water paarmeters...
Is that "Hardness" Carbonate hardness (KH), or General Hardness (GH)?
I'm gonna take a wild guess and say that what you have listed as "Alkaline" is actually KH...which would explain your drop in pH.
As carbonate alkalinity (usually referred to as carbonate hardness) falls...so does pH
Most of those reagent type test kits can only read at a resolution of 1 degree of hardness (1dKH). One dKH is equal to 17.85 ppm
So a drop from 60ppm to somewhere below 17.85ppm (it's not really zero yet) would explain the drop in pH.
Depending on the temp that the biochar is made...it can drastically raise your pH...or hardly at all. Again, it depends on the temperature used to make it.
Vlad is right. I always get the 2 names mixed up LOL. The first time I ordered Potassium Hydroxide I ordered Sodium Hydroxide instead. Thankfully I didn't use it in my tank. It does make a great drain cleaner though.lol