Backyard Aquaponics
A place to discuss aquaponics

Thanks for the feed back!

I currently have just 50 gold fish - average size 3''. I decided to go super conservative during the beginning stages and I did lose about 10 fish in the first 2 weeks. During that time, I only had a about 1/4 of each grow bed planted with head lettuce. Since then I have greatly increased dissolved oxygen by adding two air stones and a spray bar and starting using an aquaponics grade feed.

I have continued to plant the GBs to about 90% filled. This whole time my ammonia, nitrate, and nitrite levels have been damn close to 0, while the pH has been around 8. I have been adding seaweed extract weekly and have only just added iron chelate.

The lettuce, at first, was growing but didn't look lush - this was quickly remedied by the seaweed. Kale and chard started out VERY slow then took on a pale and burned look. Chard has just started to look better and hoping the iron will help with the kale. (have been assuming because of high pH kale unable to absorb iron)

My GBs are each 8'x3'. If 7.48 gallons / cubic foot = 180g. x 2(GBs) = 360 gallons.

Assume 60% of GB space is filtration (grow media) = 60% of 360 = 216 gallons.

By Jeff's NEW rule of thumb of 1 gold fish : 2 gallons of filtration = 108 gold fish

I think my system could handle more fish. If there are 50 in there now and I double that, I think the plants and the system as a whole would benefit. Thoughts?

edit: 150 gallon FT and 150 gallon sump.

Hmm, I wonder if I should put more gold fish in my system then. I've put in only 2 small sacrificial goldfish for cycling and my growbeds are about 25 gallons. If my plants are still small, does that sound okay? Should my final goal be around 10 goldfish?

I've been a bit worried since my sacrificial cycling goldfish seem to be quite cheerful instead of angsting about their lot in life.

I think you should go ahead and double your fish stock and then test regularly for a few weeks to see how things go.

If your ammonia goes up suddenly be prepared to stop feeding for a few days and even do some water changes if necessary.

Regards, Martin.

Thanks for the vote of confidence Martin. Will check back in a few weeks with updated results.



Jeff's Rule - 1 Gold Fish : 2 Gallons of Filtration (Wet Grow Media)

Levi - if your grow beds are 25 gallons, then you would take 60% of that (assuming that the grow media takes up 60% of space in grow bed) and divide by 2.

60% of 25 = 15

15 / 2 = 7.5 gold fish

Ah, okay. Thanks! I'm still getting the hang of this all.

7.5 gold fish. Damned pet shop wouldn't sell me half a fish... Now I'm over stocked

I solved it. I put in an extra gallon of wet media in my grow bed
Thank you all for your perseverance and mathematical ability.
I have learned yet again.

Lol.

I can understand their concern, selling fish halves is fraught with danger. Do you want the front half or the back half? Or do you want the bottom half or the top half? All very complex.

lol

Martin it's probably because most people would only buy the back half as a replacement for the tails that have been eaten off their own fish and the store is left with too many front halves

I am still trying to find the lower limit of my fish bio-load to grow wet grow media ratio. I originally had 35 goldfish (2") to 200 gallons of wet grow media. But I would never register any Nitrates. Ammonia 0.25, Nitrites 0.00 and Nitrates 0.00.

I recently added 20 more goldfish (1") but still have not tested the water. Want to wait a few weeks to get a more accurate change.

I will let everyone know my findings later in a week or so. And I guess people can extrapolate from my experience and compare to their own experience.