Backyard Aquaponics
A place to discuss aquaponics

What's happened to the fish in the pools AlexP?

I think you'll find those linked very closely. more to the point of it having nothing to do with hygene and probably a LOT to do with PH shock going from a low ph to 7.6 after the addition of the shells back to 6 again after a waterchange.....................

as a rule more than a 0.5 ph shift in 24hrs should be avoided...........i'm assuming you also didn't match the temp of your rainwater to your tank temp?

Native (indeed many fish) have a wide ph and temperature tolerance range, what they do not have is a liking to sharp changes in either of them

Reading reading reading, lots of reading to do!!!

Here is My understanding about several of the issues you have already encountered.
The higher the temp, the less DO the water will hold. Without aeration, hot water can be very quickly deadly.
The toxcicity of Ammonia increases with the pH.
Sudden changes of any sort are usually hard on creatures.
Sudden changes in temperature (in either direction) can greatly stress, even kill fish.
Sudden changes in pH can stress/kill fish and also hurt your bacteria's ability to process ammonia/nitrite.
pH that is too low will stop your bacteria from working properly.
pH that is too high can make it difficult for your plants to take up the nutrients they need.
Rain water is usually a little more on the acid side compared to well water.
Well water may come out of the tap reading a pH around 7 but after outgassing, it may read something much higher.

I'm sure I've missed some so hopefully others will chime in.

There you go, the bridging AP course, TClynx has done all the hard work for you. no excuses.

RupertofOZ , the fish in the pool lasted about 2 days, the pond got aeration operational about 36 hours after fish entry, by which time it was mostly too late, they did survive the first night without aeration - mostly.

OutbackOzzie , I'm down to the last survivor, and its not not looking too sharp.

steve, your'e probably right, in that the pH swings would probably kill the fish anyway, What I was referring to was that the shell did seem to start the this second wave of deaths, the fish in the aquarium had stabilized quite nicely before i added the lone shell, (is one shell (3 cm long) going to pH shock?) and then they started dying.

TCLynx , good summary, any advice on pH buffering, are shells too high? does fish poo lower pH more than fish wee raises it? have i got this back to front? with gardening, manure is an acidifying process.

soon, i will focus will be on the plants side of things, once i figure a cheap/cheery way of doing a growbed.

still waiting on the sparkie for an outside power point .... don't plan to pump without it.


on a different topic, was up at Colundra at the weekend and saw a street advert for growbeds, had a little chat with a bloke at slimline rainwater tanks factory, they make some neat stuff, something like what i'ld use as a 2nd system. (my system is temporary in nature, molded plastic or steel is a later, more considered option.)

Well, I've got lots of shells in my system, probably close to a ton at the moment. Between my water and the shells, the newer system pH is only just starting to come down (the two big grow beds in this system are filled with a mix of river rock and washed shells.) My well water after degassing is around 8 and the shells when first put in the system seem to cause even water with a low pH to jump up to 8. As the bacteria works on converting the Ammonia into Nitrite and the Nitrite into Nitrate, they seem to cause the pH to try to drop. My older system is running a very constant pH of 7.6 so far and it has one grow bed full of washed shells, while it's other two beds are 1/2" quartz based river rock.

So, are shells too high. No probably not but in the short term, they are likely to be too high.

Advice on buffering a system with shells (well this bit of advice is for anything to do with pH) do a little at a time if there are fish or plants in the system. What could have happened with that one shell you added is if the pH was quite low, the sudden addition of the shell into it caused it to start disolving and therefor bring up the pH quickly. That in and of itself may not have killed so many fish except for the fact that your ammonia was probably high which is more toxic as the pH rises. Between so many stressful events, even if a fish doesn't die right away, their immune systems can be compromised making it difficult for them to remain in good health.

My real advice for getting a system up an running (especially if it is going to have large amounts of shells in the grow beds) is to get at least one grow beds installed and if necessary a small temporary pump so you can start fishless cycling, this should help you get your system paramiters stabalized before you add fish, then when you do add your fish, you can do it by slowing getting them used to your water paramiters and then you just need to learn to balance feeding with the grow bed's capacity to handle the waste.

Guess what, I have no fish yet and I have two systems!!!!!! I've been harvesting lettuce from one system for over a month now. Fishless cycling is cheap and easy.

please stop buying and killing fish before their time.

Get the sparkie in to fix the power problem, get your pump running through at least one growbed and WAIT longer for more fish.

PATIENCE please

Alex, I have to agree with Jaymie .....

There's really only two reasons to keep fish......

One, to grow them and eat them..... two, to stuff them and hang them on the wall.

Sorry mate but 50 fingerlings hanging on your wall, just isn't gunna impress me

sparkie coming next Friday

When does the growbed(s) come?

Should we schedule the 1st ever AP intervention?

grow bed question?

any suggestions out there for suitable growbed arrangement that fits between the ponds and the fence. measured distance ~1m available for both access and growbeds. I'm thinking of 2 grow beds as the ponds are different heights.

nb on page 2 the fence can be seen on the right hand side, the shed is in the neighbours yard.

bathtubs or blue drums

Or wood frame and pond liner.
Or plastic storage bins.
Even buckets!
You really want more grow bed volume than you have fish tank volume. The less grow bed you have the fewer fish you should stock.

Its been my experience that fish can handle a couple point drop in pH. On the flip side a half point rise is death. I cannot verify all species but am certain it is true of catfish fry.

Hope this helps someone.