Backyard Aquaponics
A place to discuss aquaponics

When feeding a system heavily the bacterial action will naturally bring pH down over time.
If there are anaerobic pockets, that could elevate pH (big mat of decomposing algae that turns into a sinking mass, that could be anaerobic enough to explain an elevated pH that can't be explained by source water.)

I would not expect feeding to elevate the pH unless your system is such that the feeding actually really spikes the ammonia levels when you are also getting the elevated pH readings. No I don't see .25 ppm ammonia as being enough of a spike to do anything to the system pH.

In fact what is more common is when the pH falls too low, too fast, there can be an ammonia spike due to bacteria crash from the pH dropping too low too fast for them to compensate. Luckily you can sometimes recover from this sort of crash since ammonia isn't as toxic to fish at lower pH levels.

Algae is DEFINITELY capable of producing diurnal pH swings.

I was getting the ph rise all week prior to my post, it was the first apearence of the algae bloom and the difference morning/evening seemed to be getting bigger, the photo looks very green but actually its not that bad, i gave a small feed in the morning and hence the slight ammonia rise that day as the fish had gone a week with no feed because my nitrite was at 2ppm, its now dropping slowly.

I gave the small feed as the ammonia reading was 0 or almost all week and i didn't want to lose the bacteria.

that leads to another doubt:-
if i stop feeding for whatever reason will the ammonia produced by the fish breathing be enough to keep the ammonia bacteria going or will some dye off?

don't stress about not feeding, you have fish in there and you want the bacteria to catch up with the nitrite before you really start to build up to a higher feed level anyway. Cycling up with fish is always slow. Relax you are doing it right. Block all the light from the water till the algae goes away and then only let enough light at the water so the fish can tell the difference between night and day.

Cycling with fish doesn't really take any greater length of time.. than fishless cycling...

Todays water test

Ph 7.65
Ammonia 0.0-0.25 ppm(only a slight trace)
Nitrite 1 ppm
nitrate 20+ ppm
water temp 20.8ºC


3 Days no feed
The nitrite seems to be taking a long time to lower, i tried a dilution to double check but not sure i did it right

4 parts well water(no trace of nitrite) and 1 part FT water total 25ml water, of that i took 5ml and it came out at 0.25ppm so i take it my nitrite is 1.25ppm is that correct?

Water test this morning

Ph 7.5
Ammonia 0.0-0.25 ppm(only a slight trace)
Nitrite 0.5 ppm
Nitrate 20+ ppm
water temp 21.0ºC

Both Ph and Nitrite dropping, almost there

3rd growbed almost ready to put online. When i put in the clay pebles i was getting a ph of 9, apparently its the dust and stuff left over from the manufacture so using the ST that it sits on i've been washing it through circulating the water from bed to ST(its not connected to the main system yet) and back, ive been adding ph down to the water in the sump then pumping it back through the GB and letting it sit for a few hours before draining again, its now down to about 6.5 which is just slightly higher than my well water.

Had a problem in my hydroponic system this morning, the res and pump were almost dry, i think maybee the cat was prowling arround and must have caught one of the feed pipes and pulled it out, hence the nutrient water had almost drained as its on a 30/30 min cycle, luckily the res was only half full as its almost time to change it so i only lost about 40litres. It was ok yesterday morning and i never looked again till this morning, lesson learnt, keep the cat out of the greenhouse and check more regularly.

Good to see your system maturing in great fashion Derek!
Do you have plants already growing ?

Is the hydroponics system in or outdoors ?

Thanks peoples, not long to go to be cycled, maybe another week.

Yes i have plants growing although they are small at the moment. Lettuce, beetroot, Cabbage and Brocali(rumanesca type) and coliflours and some radish, i ate the first one today, no earth taste like the ones from the garden and was it hot, almost like a pepper

My hydroponic system is in the greenhouse, i'm slowly dismanteling as the crops ripen, i only have tomatoes and sweet peppers left growing, and i also moved the strawberies into the garden, the nutrients i was using are from GH and not cheap for what you get back when growing only vegetables, if i was growing your type of veg it would be ok its one of the reasons i have changed to aquaponics

Just got the 3rd bed online this evening(i'm just this minute in, 23:30h) was making sure everything was running smoothely, i was delayed slightly because i had visitors and they stayed longer than expected

got some photos to upload tommorrow, its a bit late now.

This is the first raddish i have uprooted its the one that was right at the edge of the clear GB, there are a few more almost ripe too. I was quite suprised at how hot it was and the distinct taste compared to the earth ones.

Had a bit of shift arround to make way for te 3rd GB and sump and ended up feeding water to the small plastic gb with an air uplift, i didn't even have to modify the syphon for the lesser flow.

New bed in place and filled just need to connect it to the system and plant.
I have a different media in this one, its expanded clay but smaller than the normal, its 8-12mm and cost 9€ for a 50 litre bag. I had to steep and wash it a few days to get the ph down as at first it was over 9 due to dust left over from manufacture.

Water test this morning

Ph 7.5
Ammonia 0.0-0.25 ppm(only a slight trace)
Nitrite 0.25 ppm or less
Nitrate 20+ ppm
water temp 19.7ºC

Gave the fish a feed now that the nitrite is almost Zero.

The water in the FT has cleared up nicely, the IBC is full to within about 10cm from the top so i recon about 950litres to give you an idea of the depth, the slight colour to the water is maxicrop and my crap photography with my iphone and also the sun.

With 950l FT and 3x 600l sumps there is about 2750litres in there now. I only have fish in the main tank but i also have an option to use any of the sumps too. The goldfish will probably end up in one if i can find anyone that is willing to sell live rainbows, there are plenty of places you can buy dead but they are not allowed to sell them live, its a local bylaw to help stop them taking over the rivers from the natural brown trout.

Now i'm almost cycled i celebrated with a few more Koi and a big goldfish but i'm still limiting the feed till i get to the magic zero nitrite. I think my total now is 12, 7 goldfish and 5 Koi.

In some of my photos you can see a large hoophouse/polytunnel without polythene, it is covered in netting and its where i keep some of my birds(another hobby i have). I keep ornamental pheasants, peackocks and pure bred chickens.

3rd GB connected and some plants put in, just a half dozen beetroot and a few lettuce as adding another 600litres has dropped the nitrate level to about 5ppm and i'm hardly feeding at all till i get to 0 on the nitrite. I also covered the new GB and sump with blackout sylage polythene.

On the subject of the plants, growth seems to be struggling on all but the leeks, i planted the same in the ground to get a comparison on growth and sorry to say the ground is doing far better than the AP so far other than the leeks which are about on par. Could it be nutritional lockout due to the system ph being high during cycling? I have been adding maxicrop, about a cap per week and also some chelated iron as the maxicrop that i could get doesn't have it and i was getting some leaves turning yellow, the newer leaves seam ok.
Hopefully that was the cause and with the pH now dropping slowly(7.5) things will improve as i have had nitrates over 20ppm for a few weeks.

Since i changed the feed to the Ft from the pump to 25mm the level has risen a couple of cm, using a 40mm outlet in the SLO there is no longer much excess for my spraybar so i have decided to upgrade to 50mm outlet outside the Ft to see if i can get a bit more flow, i'm not expecting much as the pump is only small and i think i'm doing well with it as its only 1250l/h output and i think i'm getting that even with a 53cm lift(the pump has a 3 meter lift if i remember) I'll also be ready for a slightly bigger pump when i decide which one and keep the Eheim as a spare as i want to add some towers for strawberries and herbs ............. you know the story

Yea, probably more a matter of perception since cycling with fish tends to be more stressful for many people and therefore seems very slow.

Ah man! I am so jelous of your system Derek!
16 days to I move in to the new house with a garden, SCORE!

You may see some lockout, indeed. I'm at work so I don't have the graph, will post it when I get back home.
Sinse you run all these different types, it may be hard to find a absolute pH, because different species need different nuts levels.