Backyard Aquaponics
A place to discuss aquaponics

System is fu%$ed right up.

Reading this morning (remembering that I did a 40% water change lat yesterday afternoon:

Ammonia - .25 to 5
Nitrite - 1 (at least)
Nitrate - 40 to 80
PH - 7.5 to 8

Bacteria is clearly converting ammonia to nitrite and nitrite to nitrate, but not quickly enough. Also the plants are not pulling the nitrate out as quickly as I would like.

Have put the followign measures in place:

1. Done another major water change
2. Stopped feeding
3. temporarilly put my 12v DC pump into the system, pumping water through some filter wool to possible pull out some solids - but as importatn to add extra aeration.

Later on I will also cover the tops of the ponds with black plastic (edit: will go and get some panda plastic as the days are starting to get hot here and will soon be experiencing water temp problems). At the moment they have 80% shade cloth on them. I suspect my problems are mainly algae related. The water in my system is quite green in colour, without any large particles.

I also think that one other problem may be that my second pond (which feeds into the main one by gravity - keeping the 2 at the same level) does not have any aeration of its own as the return from the grow-bed and the bubbler are both in the pond with the fish in it. If I have time later I will put a junction in the bubbler tube so I can have aeration in both ponds. Int he meantime the second pond is getting some aeration from the temporary pump setup.

only thing i can really think about is DO VB.

And again, you have already done the right thing added air and stopped feeding

Yep, keep the feed right down to a low level for a while.. Did you increase your feeding rate recently?

I have some similar problems with my small system on the back verandah, too many fish, not enough growbeds, water quality is a bit crap (my official testing standard ) and gets worse if I feed them too much..

Solution...?

Get more growbeds.......

ph will drop again when nitrification kicks back into top gear.

Hey VB, can you make a post af everything you've done to your system in the last 7 days?

EB/Steve - I probably did start feeding the fish a little extra because my nitrate level had dropped from 160 to 10 and I wanted to make sure my plants got some food. The last couple of days though the fish went off the food and although I reduced the quantity accordingly, some may not have been eaten, contributing to the problem.

When I first got my test kit (only 1 week ago) I tested the pond and it had a high PH then. At that point I had 0 ammonia, 0 nitrite and 160 nitrate. I added the new grow-bed that same day and removed the plug from the pipe that joins my 2 grow-beds, which meant I added another 300 litres to the system.

Given that in the past my issues have been with low PH I can only think of 2 things that my be causing the high PH. The first is the obvious algae bloom - which started a couple of weeks ago I guess. This may have been caused by me taking off a polystyrene cover that I had on top of the pond (for insulation) and replacing it with plastic and a 80% shade-cloth cover. Sun has also been more intense. Given the nitrate levels, it is not suprising the algae has done well. The algae is a type that makes the water green, but is not stringy or anything.

The second is the couple of handfulls of shell-grit that I have in the system. I have now removed this just in case it is causing the problem.

To deal with the algae issue tonight I have put panda plastic on the top of both of the ponds (white side up). Virtually no sun will get into the ponds now. Only time the water may get some sun is when in the standpipe an maybed a bit at the top of the flood cycle (though my beds don't flood above the gravel). Once the algae is under control I may remove some of the panda plastic in favour of some shade cloth again - as I am not sure the fish will like being in the total dark all the time???

I have also put a T join in my air pump line and now have a line going to the second pond - which is fishless (other than the odd goldie that may swim through the pipe that joins the pond). Although the water in the ponds exchanges over time (as the levels rise and fall in the flood and drain cycles) it probably takes a while for the water to change over - and given the return is in the pond that has the fish, the fishless pond has probably been fairly devoid of oxygen.

Anyway - hopefully all these things will help.

PS - Steve, you will gather that I have done quite a bit to the system in the last 7 days (though nothing stupid I hope). BTW - transferred the last 10 or so of my fish from the fish tank to the pond on Saturday afternoon before I realised that the pond was not in good nick (bugger). This has not been a contributing factor, but all my eggs are now in one basket so hopefully everything will be good. Will do nore tests tomorrow night when I get home from work and see how it's going. I wonder if as the algae dies, this will cause further issues with the system due to it decaying??

VB, man you know more than you let on

Algae die off will increase BOD (biological oxygen demand)

Your problems are probably cause by a few small things adding up. The biggest one is probably lack of DO.

The uneaten fish food will have further raised the DO demand

Then there is higher load on the biofilter from the new fish put in.

I'd keep the shell grit in there (at least half of it anyway) becasue ther eis going to be some serious nitrification going on in the next week, and we all know how that drags the ph down (of unbuffered water). At the very least keep checking PH and make sure it doesn't drop below 7.0

Main thing is to keep DO as high as possible, IMHO.
Cut the feeding RIGHT back for at least two days, the fish will be fine

Your readings aren't THAT bad, VB, but i feel your frustration, its always annoying when something "goes out of wack" for no apparent reason.

Maybe just leave a corner off the panda plastic, so the fish get the sense of day and night.

MY water is really green too, i might go out and test nitrates haven't check it (ever i think) in the 1000lt. Maybe this is a good bit of experimentation for keeping lower nitrate levels (via bigger more heaviliy planted grow beds) esp. during the summer when the water gets heaps of sun?

All in all VB, you've got your finger on your systems pulse

Not just a pretty face Stevo. Readings tonight:

Ammonia - 0
Nitrite - .25
Nitrate - 80
PH - 7.4/7.8

There is already a noticable difference in the greenness of the water (algae dying off I guess).

Will monitor over next couple of days. Should be feeding the fish again at a reduced rate within a day I reckon.

I might cover my tank for a week or so, my water is very green, and the sun the last few days has been intense!

Do you think 80% shade cloth will do it? will be much better than with nothing!

DO demad will go up though, as the algae will switch to consuming O2.............

The algae still seemed to flourish with 80% shadecloth on my system. Go the panda.

cool. Off to the hydro shop for me

"i need it for my fish tank.........." LOL

Yeh - I find myself saying that sort of thing always. Why I feel I have to justify myself I don't know.

I made some small adjustments to my system last night. These included:

- raising the end of the return pipe about 50mm (to ensure there was a bit of a fall of water even when the pond was totally full - to help with aeration)
- Cleaning the pipe from the pond to the grow-bed to clear build up of algae from last 3 or so weeks (as I have temporary plumbing still, this pipe is a clear type pipe)
- Ater cleaning the pipe, making a sleeve out of panda plastic and shrinking it onto the hose with my heat gun (this will stop any future build up of algae).

Why I am talking about this - well it totally changed my flood and drain cycle times. I noticed when I went out to do the tests tonight that the grow-bed was flooding nearly to the top. I then changed the timer so that the pump is on 15 minutes and off 30. Drained fine in the 30 minutes, but even in 15 minutes the bed flooded too much (above the gravel level).

The reason I expect is 2 fold:

1. More water flow to the bed due to cleaning the pump pipe
2. Drainign slower due to raising the far end of the outlet pipe closer to the horizontal.

The moral - little changes can have significant effects. Will probably drop the pipe again tomorrow to get the cycle back to something workable.

I also think that the timer is not working particularly accuratelly. Will time it tomorrow.

VB, unless the outlet pipe is "flooded" with water it shouldn't alter the outlet flow rate

The drain is quite narrow so I think the extra fall helped increase the drainage rate. We will see when I change it.

Probably did then, what i was getting at was that if the flow was completely filling the outlet pipe then a greater fall will "siphon" more than a horizontal run.

In my case, where the flow only takes up the bottom qurater of the outlet pipe, it wouldn't make a diff.

That was the only concern i had about flood and drains. I think that having an oversized drain pipe to the tank would help.