First AP system build!

[Adam Klieg]

Hi all,

This is my first attempt at aquaponics. I used two IBC totes. One is cut to 12", leaving the bottom half to the fish tank. The other is cut to 18" and 20", using one as a media bed and one as a raft (with the option to switch to media if preferred). The media bed is up top, gravity draining to the two lower rafts and back to the fish tank.

The media bed is going to house lava rock and be a constant flow (no bell siphon). I put the drain pipe roughly 1/3 from the bottom of the tank to create a reservoir of water which has 2 airstones oxygenating that standing water. We built a 1/2" PVC frame, drilled with 1/8" holes to act as a drip system over the lava rock. We believe this will work like the Dutch Buckets or a recirculating deep water culture.

Each bed and the tank has 2 airstones (8 total) with an air pump that pushes roughly 4 cfm. I aerated water for 24 hours and added 11 goldfish to get the system cycling. The fish were a little stressed from a rough transport but they are doing much better this morning and even ate all of the duckweed that came with 5g of water from a friends aquarium. 

Please feel free to critique and leave suggestions as this is a learning experience for all. I will be added vertical growing space on the walls and a plant starts table after I get the rafts cut and painted. 

Thanks!

[Adam Klieg]

Well so far I've had very little water loss, if any but there are only 11 smaller fish and no plants, we'll see what it looks like when the system is filled.

Paul came over on Tuesday and helped figure out the positioning of the netpots (2"). We went with 7" centers. This gave us 35 holes on a 37"x44" raft in the IBC. I have 70 holes available. What are your recommendations on the media to germinate into and use inside the netpots? Are there any varieties of smaller headed lettuce, kale, collards and herbs that seem strong in AP systems (going to make a seed order)? Any recommendations for strong fall/winter crops to order seed of? If anyone would like to split a seed order, buying larger quantities usually has significant discounts!

[Jon Parr]

Adam, how many catfish in 175 gal? It is my opinion that FT volume matters little in determining stocking density. In fact, hi density stocking may help mitigate aggression, or breeding behavior, and thus be advantageous. What does matter, is biofiltration capacity, and nutrient draw. Common advice on these forums is 1 lb fish to 5 gal FT to 10 gallons of Media, with a seasoned max of 1 lb of fish per cubic ft of media (7.5 gal). Rafts and hybrids have less agreement on stocking densities, but I think again about 1 lb max per sq ft of planted area. Ibc's are what, 12-15 sq ft each (I don't use ibc's, they're fugly)? So three ibc's planted is near 40 sq ft, so I'd go a max of 40 lbs o eventual fish size. Cats are usually eaten 2+ pounds, so maybe 20 catfish. I'd also put in a few bluegill in addition (variety is the spice of life), and eat/stock as needed to maintain 40 lbs or less. Keep in mind that the plants themselves (actually the roots) become a major part of biofiltration in raft systems, and major tear out and replant will throw things off balance. No biggie unless you are already stressing your bio-load.

[Adam Klieg]

Hi all,

Yesterday I noticed white patches on some of the catfish's fins. On the catfish that has it the worst, it looks like a piece of solar salt. On the others, it is still very small and is almost like a pimple. I tried to get a picture, but no luck. I looked into this and it could be ich or collumnaris and it seemed the only thing to do with catfish is to raise the salinity. I added 1 lb of solar salt to 500g of water (just under 3ppt). Does anyone have any other suggestions as to what this could be and treatment for it? I appreciate your help!!

[Jon Parr]

Hi Adam, just noticed this entry, seems my gmail account has been randomly throwing notifications in the spam folder. Great. Anyway, it may be to late, but it sounds like Ich, and you can treat with salt and raising the temp to the mid 80's (speeds up the life cycle). Cats can take 3 ppt, which is .3%, which is a lot more than a pound per 500 gal., you actually need 12 lbs of salt to reach 3 ppt in 500 gallons. I use course rock salt from HD or Orchard, $5 per 50 lbs.

Use the formula (FT gallons) X 8 X .00S(S is your desired ppt, in this case 3) = pounds of salt to add. So for you, 500 X 8 X .003 = 12

The change in salinity is what kills Ich, not the salt itself. So I do a water change, bring temps up, add salt all at once and keep it salty for a couple of weeks (meaning if you do any more water changes, add 3 ppt to the top up water). After two weeks, do daily 50% water changes with fresh water at least 3 time (1st change nets 1.5 ppt...2nd nets .75 ppt...3rd nets .375). This is a good level to keep salt at long term, for the health of the plants and the fish. If Ich persists, do it all again.

[Adam Klieg]

Hi Jon, I posted this in the catfish forum as well and got some great feedback. That's interesting that it's the change in salinity, not the salt that kills ich. I raised the salt to 3ppt with 12 lbs as you said. The water is consistently about 74-78 and I don't have a heater but figured that temp would suffice. About 5 days later the white spots are disappearing and almost can't even find them. I appreciate you letting me know what to do from here and how to get the system back on track for plants. The water hyacinth that was in the system does not like the salt at all, had to take em out. Thanks always for your help. Hope to see you this weekend!