Backyard Aquaponics
A place to discuss aquaponics

Nice setup Brian you must have plenty of money if you can afford Glenfinnic scotch

No F and F... It's just the tin that I have my sewing stuff in. I have no idea where it came from. Thanks for the complement on the system though. The ammo was converted to 0 within 24 hours from 2 so it seems I am ready for fish. I am going to dose it heavily this evening and see how it copes. Is there any way to predict what sort of ammo production a certain weight of fish will have in a system so I can check how it will cope with the load from the fish.

Well I don't know the conversions for figuring how much fish will produce how much ammonia and it is of course going to depend on the type of fish and type/amount of feed they are given. If you are able to dose up to 2 ppm of ammonia and then a day later have both ammonia and nitrite read 0 then you are ready. Make sure both ammonia and nitrite read 0 before actually buying the fish. A few days without dosing is often good if you will be getting fish soon.

How much fish to estimate for the system, well base it on how much flood and drain gravel beds you have. Recommended stocking levels are something like 2 kg of grown out fish per 100 liters of grow bed. So if you plan to harvest fish at about 500 grams, that would be as much as 4 fish per 100 liters of grow bed. You don't have to start with that much right away though but if you get small fish that number will be fine as you will be slowly increasing feed as the fish grow. Still keep an eye on water test results.

Dito as above

well in a 24 hr period the ammo goes from 2.4 to 0 but the nitrite is still left hanging at about 0.3 so i guess it is still a waiting game. If one does not add small amounts of ammo to the system is there not a chance of all the ammo converting organisms dying off? I think I should be dosing small amounts of ammo until it is cycled to simulate having fish in there or no? Plant growth still looking good.

If it is gonna be a while before you get fish, then small doses of ammonia (and I mean small, no need to dose up to 1 ppm or anything like that) could be in order but if you are going to be getting fish in the next week then you could skip dosing and probably be fine. If there are any solids (leaves, debris, dead bugs) in the system that could be breaking down, they will slowly release ammonia, granted, this is very slow release in a new system but in an established system with some build up, it can keep the whole thing going for yonks without fish or dosing of any kind.

Getting past the nitrite is often the hardest part. It seems that in some new systems the trace nitrites take a long time to go away completely.

Good Luck

ok the latest readings indicate ammo 0 nitrite less than 0.3 and average nitrate. It Takes a little longer than 24 hrs but it is a large system. I would so like some fish now. Ph is still a problem at 8.5 but seems pretty stable there. If I where to salt to 3ppt how much salt to add in grams? given nearly 8000 liters of water. Could I not just add some vinegar to the main system just to get pH really down for the fish that arrive in pH 6....? The temporary holding tank idea is not too successful as it is now cycling its filter and spiking all over . I recon it will be useful in the long run though. I tried some commercial pH down stuff and it did nothing! It gives absolutely no clue as to how much of the stuff to add on the bottle. It seems it is for a small aquarium as I added a couple of cap fulls to the 600 liter tank and nothing! It looks salt like but a little different. what could it be?

So Plan: salt, and add vinegar, then get fish and dump them in. even if the pH rises again the fish can get accustomed to it slowly. (or not?)

By the way temps are now hovering around 10 chilly degrees... Will trout even grow at 10 degrees?

Ok keeping in mind that bouncing the pH will be detrimental to the bacteria you have been working hard to grow, but if you really think you want to go dumping some acid into the system. Try it several days before you schedule to go get the fish so you can see how far you manage to bring the pH down and then how fast it bounces back up.
Problem is many buffering materials will simply dissolve faster when exposed to acid and therefore bring the pH back up fairly quickly. If you are going to do something that could cause a major bounce, I would suggest doing it before you have fish in there to suffer the experience.

You can try it and see.

My experience with my system full of washed shells is that acid will only bring the pH down over night, by the next morning, the pH will be back at my normal 7.6. They only way I've really found to bring the pH down in any of my systems is feeding the bacteria heavily (or probably more accurately, the break down of the solids that has built up in the grow beds along with the bio-filter working under a heavy feed load and even then the pH shift only lasts as long as the heavy feeding.)

Well TCL I knew I should have just taken your word for it but I had to go and try all the same... dumped 4 liters of vinegar into the system and watched the pH. It went down to about 6 and 24 hrs later it was back at 8. . So much for that! The other tank is exactly the same story.

So new plan: Get the fish in smaller batches say 2 kg at a time in my 200 liter barrel and then get them to the farm. Once here I can run an airstone into the barrel and slowly over 2 or three days up the pH, and then dump them into the system. If all goes well I go for some more. It is kind of on my town route so no big extra expense as I am traveling there anyway. I figure as I will do water changes to the barrel from the main system to up the pH there should not be too much of a chance of the toxicity levels getting too hectic over two or three days. A small cycled biofilter would be a real asset right now. I think I must build or buy one for this purpose. Should I salt the barrel water? 1Kg per 1000 liters? 200 grams in my 200 liter barrel.

I am a little confused about this pH thing. I am understanding that if you add acid it basically just disolves more of the stuff in the water that is responsible for the high pH so the pH just bounces back, or does it disolve other stufff like cement in the walls or the media?

Correect Brian... until the "buffer" in your system water has been used up... the pH will bounce back...

And yes it is possible that the new concrete/cement tanks may contribute to the buffer for a while...

As you cycle, and the system matures... a combination of bio-film buildup on your tank walls... and the natural acidification of the nitrification process.... will move your pH...

Albeit... you might not come back much beyond 7.0 for the first year... at best...

And bear in mind... any further top-ups of the same source water... will "buffer" the system and pH...

You're best off treating the pH of any top-up water... a smaller volume... than continually trying to move the pH in the main tanks... although initially it might be worth doing so....

Finally I have fish! On Friday I drove out and picked up 30 250 gram trout. They are actually quite big already. It was just a test batch to see how they would cope with the pH change. The oxygen ran out half way back and had me in a bit of a panic but we got back and all was fine. I put them on the air pump then. I intended slowly moving the pH over a day or two but after changing out two buckets of water the pH had already shifted from 6 to 7,5 done over about three hours but the ammonia was getting towards dangerous levels so I floated a tub in the main tank and shifted them in there. Then over about a half hour of slowly shifting water from the tank to the tub got the temps more or less the same. Then I released them in the tank. This morning there where no floaters and the fish where very active jumping the surface all the time. They even eagerly gobbled up a handfull of cat pellets that I tossed in. No feed yet. I will pick some up on Monday. I am very happy!

The sump is giving me a real pain. I should have just built a brick sump. The rain we have been getting has caused the one side of the sump to conk in and the sand under the concrete ring collapsed. We set about breaking away the entire concrete ring today and dug out the sand from around the sump again. I am going to get a few bags of cement and mix it in with the sand as we refill the sand around the sump. I will also recast the top concrete ring and put a whole bunch of bolts through the plastic to anchor into the concrete and support it. It should do the trick.

add the fish and go with it, and live with the results. You can only 2nd guess so long. I think that they will adjust,

watch your system and only intervene if it gets way out of the parameters, it will find its own level.

Enjoy !

Congrats on the fish! And on them surviving. I wouldn't worry to much about the pH. Like others have said, you'll notice if the fish are acting stressed. As long as the system is cycled (which it is) and the fish are acting normal, let it go! Let their actions be your guide!

All is going along well. No fatalities with the fish so far and they are ravenously hungry and I am not too sure how much to feed. I have been told 1.5% of their weight per day adding the food weight and the last weight together to get the next days amount and so on and so forth. seems like a bit of a hassle all that weighing and also what about the rate of metabolism changing with the temps. I am now seeking alternatives for live food. Mosquito larvae, mealy worms, earth worms, maggots, daphnia, tadpoles and mosquito fish are all on my hit list so far.

I have amassed plenty of stuff for a new smaller system. I have the old tank from the gutter system, 4 half blue barrels with stands and two other nice strong plastic tubs for growbeds and a very nice roto molded green tank for a sump. this one I would like to run on a constant pump with autosiphons or loop siphons. the ft and sump are about 600 liters each and the growbeds are about 600 liters too. I think if I can get it going soon I could run it in a small greenhouse and do cucumbers and get tilapia going to replace the trout when temps get too high. I have 4 sliding door sheets of safety glass for the roof and plenty of used steel window frames to build a small greenhouse. here are a few pics


As you can see by the holes we have been having a go at the lettuce. Very nice crispy leaves. Had some brilliant ap salads with lettuce pac choi and swiss chard with cabbage seedlings.

Looking good Brian...