Backyard Aquaponics
A place to discuss aquaponics

Nova did you ever check the pH of the rainwater straight from the tank? Living in limestone country I guess that the dust on the shed roof is going to be pretty alkaline?

NOva, i ran really clear water after i did a majority change out of my algae infested water. Was sweet until the last week of 37+ weather and corresponding blinding sunlight landing right on my tank. its starting to go green again and PH is on the rise due to the algae again. This sundays project for me is going to be shading the fish tank. Is yours in direct sunlight too?

It is not in direct sunlight, but it is fairly bright where it is. Here is a pic from earlier in the thread. Well there would be one if I could get a list of already attached pics. Have a look at page 2 for pics.

KE, give me a sec, just checking... bang on 7 out of the tank.

What would happen if I used limestone for the grow bed media? Would that affect the pH badly? It's been too long since I did year 12 chemistry.

Nova

Its a long time for me too, wouldnt that raise the pH?

That is what I assumed, thought I would see if anyone agreed with me though.

Nova

OK, there have been some developments in the past week.

Firstly, on saturday I changed about 90% of the water in the tank in a bid to try and get rid of the algae that was using all the nutes. This seemed to work, except that I used a different tank (closer to home) that had dirty water, so that although there was less algae, the water was green/brown cloudy. The tank in near the shearing shed and has gum leaves in the gutter and dust on the roof. Seemed to go alright though.

I took the opportunity to change the plumbing around, with the pipes now going under the beds and out the back of the tank. I also disconnected the duckweed tank as I ran out of threaded pvc fittings.

All was going well (if a little cloudy) until lunch time today when I checked the fish and found 2 dead goldies. There where 2 sick ones as well, so I fished out the dead ones and put the sick ones in a tub of fresh water. About an hour after lunch I checked again to find another dead fish and one of the sick ones had died.

About now Les's HSM kicked in and I decided to do another water change, but this time using the water from the tank that I have used for all the fish tanks previously (1.5km drive). Started draining the tank and went to get the water and came back to another floating fish.

On the bright side though it has rained (drizzle really, 1.5mm only), and the tank is now mostly clear as it has had another 90% water change with clear water. Before I changed the water I checked nutrients - Ammonia 0, Nitrite 0, Nitrate 15, pH 7.4.

Isn't this fun?

Nova

You certainly have your challenges put to you Nova. A 1.5k drive to get water! Look on the bright side. You will have this sorted before you get the main fishies and all will be sweeeet.

Yeah, the rainwater tank on our house ran out in June, we have been topping it up with mains water mixed with bore water since then. Have been filling a 25L drum for drinking (use it in a week or less between the two of us).

Nova

My theory on the deaths (from now on to be referred to as "the incident") has been narrowed down to two options.

1) Is that the duckweed tub was leaking bad water into the fish tank. The tub has not been connected since the weekend, and I had been topping it up with fish water as there was a slow leak into the fish tank. It was setup as continuous flow and as a result had quite a bit of sludge in the bottom. I think this started to break down resulting in bad water leaking into the fishies. Solution, the duckweed in now in another tub, not connected to anything and I will just add fish water as it evaporates.

Or... 2) I added a float from an old fish net (the ocean type used to catch fish) to hold a bit of pvc around the water reutrn to the tank like EB has in his big flood and drain setup. It really does make it a lot quieter. I did this on tuesday night. Solution, use part of a polystyrene sheet to float the pvc.

These are the only differences from the green but non "incident prone" setup from last week. I am open to other suggestions, I want to incident proof this system before getting some proper fish.

Nova

can i give you option 3?

did you check the "supply" water PH and TEMP before using it for your 90% change?

PH and temp shock can be really nasty.

When i did mine, i set it up on a relatively slow flow rate, took 2 hrs to fill 700 lts, and my tap water is same ph as my system water was.

Blimey, 2561 posts to catch up on.

Steve, I filled the new water slowly, similar to what you did. They kept dying though.

After i got some more fish a week ago and some of them died too, I took them out of the tank and put them in a plastic tub with a airstone. Some of them have still died but I am hoping that with a really good clean of the tank/grow beds and some new water they should be ok.

I think that the problem with the algae was that my single (small) grow bed wasn't providing enough filtration. When I drained the water again two days ago it was green again, but it cleared up overnight when there was only 200L in the tank (higher ratio of grow bed to water).

So, clean out tank, wash grow bed, plumb in another grow bed, add external bio-filter and start again. Hopefully I don't have any more problems.

Nova

Well, the tank has been dry for two weeks and it is now time to rebuild it (hopefully without any further problems).

I think I have sorted out what went wrong. I had too little filtration/gravel and too little water flow. I was turning over the 800L of water in about 10 hours. I hadn't worked out the flow. Once I drained the water and left 100L in the bottom of the tank, the algae cleared up overnight. The gravel also smelt quite bad, so that could have been doing it's bit too.

So, new approach, more grow beds (2 tubs with higher flow, plumb in half IBC's asap), more flow and an external bio-filter on the airation side.

Just need to get everything bone before Mon decides to keep all the fish he currently has.

Nova

Nova, its not a new approach - its a modification on the old system

Go for it

I think of it more like turbocharging it. Just add more boost.

Nova

until your intercooler pipe (pvc pipe) pops off