Backyard Aquaponics
A place to discuss aquaponics

Hey all, i've been meandering about the boards for about 2 or so months now ever since i found out all about aquaponics. I've built my own system and id like all of you gurus to please help me out in maxing out my production for my personal herb and vegetable endeavors :-)

FT: 30 Gal
FT has heater set to 75 deg.
Fish: Small Comet Goldfish (started with 5, one died, added 6, all but 4 still alive)
Fish food: i've been alternating between goldfish flakes and duckweed.

Grow room temp/conditions: this is in my basement, high 60's with humidity around 50%

Growbeds:
20 Gal Container w/ Pea Gravel & bell siphon
(sump under grow bed that flows to NFT)
2 10' NFT w/ SOLO cups filled w/ pea gravel

Lights: (18hrs on, 6hrs off)
Over NFT: 2X 4' T8 Floro tubes, each having a 6500K and a 2700K 32W each.
Over Growbed: 4 CFL's, 100W equiv, 2 @ 5000K, 2 @ 2700K

Water:
Water timing: during the 18hrs on: 30m on, 30m off.
Source: Well water
Straight from tap readings: pH 6.6-6.8, KH 240ppm, GH 30ppm
Tap after a day or so: pH: 8.4, KH 240ppm, GH 30ppm
FT readings: pH 8.8 (could be higher) , KH 240ppm, GH 30ppm

Plants in the NFT:
mostly giant caesar lettuce & lechuga lettuce [both doing well]
flat leaf parsley
a spinach
2 cucumber (yellowing, not doing well)
2 pepper

Plants in GB:
4 cilantro (2-3 leaves)
a parsley (3 leavs)
2 green onion (not doing well)
basil
tried putting seeds directly into the GB, thats where the cilantros came from... the oregano, rosemary, thyme didn't come up.

Fishless Cycling:
Started March 1st, added ammonia and tracked readings (will post graph later), saw nitrite and nitrates spike and go back down, dosed 3 more times and after those readings got close to 0 i added the fish. Readings have zeroed out since adding the fish (its been about 3 weeks) so i added some seaweed extract to the water and also by foliar spray to keep the plants going as the nitrates build back up.


Problems: From doing LOTS of research, i've determined that the 8.8 pH and the high carbonate hardness is affecting the plants and probably killing off the fish. I assumed that the gravel was the culprit so i tested it by taking a sample and putting it in vinegar, but there were no signs that limestone was in it (got the pea gravel at lowes). After attempts with dosing pH down, The 4 goldfish that are left have survived the longest (3 weeks), but i'm anticipating death any day now. I know its the source water thats causing problems. My latest attempt at putting the pH into a proper range for the plants and fish entails taking the water into a bucket and treating it with distilled white vinegar (5% acid from shoprite) and letting it sit and taking readings before i add it to the FT. I know rapid swings in pH will not be good for the fish. I've added a cap full of vinegar to the sump for the last 2 days in hopes that the acid will bring down the KH and pH.

Comments and suggestions are extremely welcomed!!!!!
I love gardening and growing, runs in the family, i want to make this project a success!!!

sorry for the blurriness

hey folks,

i'm still battling the high pH (off the scale 8.8+) and high KH. I've been dosing the sump w/ 2 cap fulls of vinegar every day, but have seen very little movement in the pH. I'm going to make a tea bag of sphagnum peat and add it to the system since i've researched it can lower pH. i'd rather not change out all of the pea gravel in the GB or the cups if i can possibly avoid it. any help would be appreciated!!!

Lets take a look at the true meaning of Alkalinity and KH

Alkalinity refers to amount of carbonates and bicarbonates in the water and water hardness refers to the concentration of calcium and magnesium. As calcium and magnesium bond with carbonates and bicarbonates, alkalinity and water hardness are closely interrelated and produce similar measured levels.

8.8 is high but I wouldnt focus too much on your KH for the moment. I would suggest that 3-4 fish is really all you want with a 20gal system anyway and if you stick with that for a few months you will find the nitrogen cycle will buffer your PH in time.

Patience is your best friend.

update:

the cucumbers have mostly died off, all other growth seems to have slowed down. down to 3 small goldfish. no luck in changing the pH or alkalinity with distilled white vinegar treatments to top up water. hardness 30ppm, alkalinity 240ppm, pH 8.4-8.8 range. this is month 3 of operation.

i've noticed yellowing in the plants and im starting to be concerned. i've been treating regularly with foliar sprays and tank additions of seaweed extract. i haven't been reading any nitrates in the system.


another question: is it safe for the fish if i add fish emulsion fertilizer to the system? my gut instinct is no, but i just wanted to verify w/ ppls on the forum.