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New system high nitrates and seasol plant advice

Discussion in 'Water Chemistry' started by kadarra, May 2, 2017.

  1. kadarra

    kadarra New Member

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    Hi guys, I have had my system running for about 1 month now with plants, but still cycling without fish. Media is 20mm gravel which was tested with vinegar with no fizzing.
    System is 1000 litre IBC fish tank, with 3 x cut down IBC growbeds all over a 750 litre cut down IBC sump. CHIFT PIST system with 3600 litre per hour pump pumping about 1.2m head. 32mm diameter delivery pipe up to a T and then splitting to 2 x20mm lines, one feeding 2 x growbeds and the other feeding the other growbed and fishbtank return. Fish tank has a 40mm SLO to a radial flow filter which the gravity feeds back to sump.

    I have been cycling with seasol (white bottle) not the power feed version, as per Murrays first 12 months video with 400ml initially and then a capful every 1-2days. I added about 3ml of 10% ammonia solution, about 20 litres of aquarium water, and then about week latet a teaspoon of urea, then 2 weeks later another 2 teaspoons of urea and finally on Saturday a desert spoon of urea. The urea takes about 3-4 days to convert to ammonia. I have done this over the last 4 weeks. I believe my system is now cycled with readings over the last week. PH has been droppiing. Initially it was fairly consist at about 7.2 to 7.4.
    25/4/17 ph 6.8, ammonia 0.25, Nitrites 0.25, Nitrates 40
    27/4/15 ph 6.40, ammonia 0.25, Nitrites 0.25 nitrates 40
    28/4/17 ph 6.00 ammonia 1.00, nitrites 0.50, nitrates 160
    29/4/17 ph 6.00 ammonia 0.25, nitrites 0.25, nitrates 160.0
    30/4/17 ph 6.00, ammonia 0.25, nitrites 0.00, nitrates 80.00 added 1 desert spoon of urea after testing
    1/5/17 ph 6.00, ammonia 1.00, nitrites 0.25, nitrates 160.0. Todays readings were exactly the same.

    Long way round of asking, but my plants basically havent changed in the 4 weeks, except the 3 chilli plants dropped all their leaves, one lettuce has died, some minor growth on the cauliflowers, broccoli are dropping some leaves, but have produced some new ones, net effect zero, the strawberries initially replanted from a dirt garden struggled but produced some fruit but now have stalled, carrots are picking up, onions are goung fair, snow peas are much the same, sugar peas have produced some pods but now appear to be yellowing off and some look pretty unhealthy. I planted some silver beet and it hasn't done much either. Chives seem to be doing ok and picking up.
    I added about 50 grams of blood and bone (with potash) to each of the growbeds and watered in lightly on Friday hoping to give the plants a lift, but no signs of any change for the better. Tonight I added about 300 litres of tank water to the sump and 1.5 heaped teaspoons of hydrated lime to bring the ph up. I also added 1 teaspoon of chelated iron last night hoping that this might be the solution to the plants distress.

    Should I still be adding seasol at this stage with my nitrates so high? Any clues on why my plants are doing so poorly. They certainly do not exhibit the lush growth indicated by Murrays videos (the first 12 months) and is actually quite a disappointment and disheartening. I realise that it takes time for systems to mature and they don't really come into their own until 12 months or so, but I feel my plants are only just surviving, and some are dying. I can upload some photos shortly.

    Any clues or help will be greatly appreciated from the aquaponics experts. PLEASE.
     
  2. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Hi Kadarra,

    It's most likely too cold for the Chilli plants.

    High Nitrates slow, even completely inhibit the growth and development of plants, especially seedlings.

    A Nitrate level of 80ppm can see tender leafy greens, such as lettuce, develop a bitter taste. A Nitrate level of 160mm can completely inhibit the development of some seedlings.

    I would stop adding Ammonia, urea, or seasol, then do a number of partial (25%) water changes every second day with 'aged' water (aerated and exposed to sunlight for at least 24hrs) until you get the Nitrates down below 80ppm, then plant out every spare piece of GB with seedlings of fast growing leafy greens, lettuce, Asian greens etc.

    Once you get the Amm below 80ppm, you could add a capful of seasol very 3rd day or so, just to keep the bacteria ticking along until you put fish in.

    I would also try and raise and buffer the water pH by adding Calcium carbonate (Garden lime), Calcium Magnesium carbonate (Dolomite lime), Hydrated lime, and Potassium bicarbonate... in a ratio of 6:2:2:1... until you get the pH up into the high 6's. This will also add nutrients for your plants while keeping the K, Ca, Mg in ratio with each other.
    .
     
  3. kadarra

    kadarra New Member

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    Thanks Hayden. I have ordered some potassium carbonate from you earlier this week. I will try the water changes and see how I go. This should drop the nitrates and boost the ph. I also have some more seedlings sprouting at the moment in a seed raising tray, rocket, bok choi, broccoletti and something else I can't remember and will plant these out as soon as they are big enough.

    I was surprised the lettuce I have planted 4 weeks ago is doing so poorly and at least one has died.
    Thanks for your help.
    Dave
     
  4. Yabbies4me

    Yabbies4me Administrator Staff Member

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    .
    ...:thumbsup2:
    .
     
  5. kadarra

    kadarra New Member

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    20170503_221814_resized.jpg 20170503_221834_resized.jpg 20170503_221905_resized.jpg 20170504_071629_resized.jpg 20170504_071655_resized.jpg 20170504_071720_resized.jpg 20170504_071726_resized.jpg
     

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  6. kadarra

    kadarra New Member

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    Bit of an update. System has cycled and pH is up and down from 8.0 to 7.4. Nitrites got to 0.00 24 hrs after ammonia got to 0.00. I picked up 10 trout fingerlings yeterday and they seem to have settled in OK. Ripped out the chillis and replanted with broccolini and added some bok choi and a few lettuce to replace the dead ones. Nitrates have dropped to about 40ppm and the plants look like they are picking up.
    I think I have a problem with brown algae though, as I cannot see the bottom of the fish tank. The best I can see down is about 400mm. Any clues on getting rid of it? I am pumping 24/7 through growbeds and fish tank. I have added extra aeration by running my backup pump on battery as well (750 gph). I have the fish tank and the sump tank fully covered, only the radial flow filter is exposed to sunlight and is a white HPDE.
    I also picked my first crop tonight - 1 strawberry.
    Any help on getting rid of the algae would be appreciated!!
     

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  7. kadarra

    kadarra New Member

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    Readings today pH is 7.4, Ammonia 0.00, Nitrites are up to about 2.00 and Nitrates are up to 160ppm. I have not fed the fish apart from a initial settling in feed until the Nitrite spike drops. Good news is the brown algae seems to be slowly dissipating. I can almost see the bottom of the fish tank. I am wondering if the brown algae has been screwing up the chemistry a bit too. I salted the water to 2ppt to reduce the effect of the Nitrites in case it went off the scale.
     

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  8. Yabbies4me

    Yabbies4me Administrator Staff Member

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    That's a big spike in Nitrate, especially considering they are only fingerlings and you haven't fed them... are you sure you're shaking the test kit reagent bottles thoroughly before use and the test tubes between adding the two reagents?... and are you waiting the recommended 5 mins before comparing with the colour chart?

    It's a good thing you salted, the 2ppm Nitrite level is enough to harm, even kill your fish if you hadn't salted. I don't know why you've had a Nitrite spike like that after the system had already cycled and you only added fingerlings... Some strange things going on with your system... Is it all sorted now?
     
  9. kadarra

    kadarra New Member

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    OK - time to fess up - Rookie mistake
    Found out I had been testing my nitrates incorrectly. No wonder I was getting high readings.
    I was adding the 10 drops of Bottle 1 and then shaking Bottle 2 for 30 seconds and then adding 10 drops of bottle 2. I was then shaking the tube for 1 minute. and then waiting the requisite 5 minutes. All as per the directions, except I missed one vital step. Inverting the tube a couple of times before adding drops from bottle 2
    See the photo below for the incorrect and the correct results.

    Tube on the left is the correct test showing 20ppm and tube on the right is the incorrect method showing horrendously high Nitrates at 160ppm.

    Now it starts to make sense.

    Not sure about the Nitrite spike, maybe there was still some residual ammonia hanging around from the last Urea dosing (but that was 11 days ago) so that is probably not it. And I reached zero Nitites before the fish went in so that doesn't make sense now that I read this back. I have been having a problem with brown algae which was pretty murky when I put the fish in. I couldn't see much more than about 250mm into the tank, but it is slowly dissipating. I reckon I can see down at least 7o0mm now. Maybe the algae breaking down is causing some Nitrite issues??

    They are fingerlings but there are about 4 that are 180mm long and the smallest is about 100mm so maybe they are producing more ammonia than expected and the nitrites are slow to convert.
    The trout seem happy enough and come up to the light when I lift the lid on the tank.
     

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  10. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Yep, the Nitrate test kit is pretty touchy, you've gotta follow the destructions to a tee.

    It might be the brown algae breaking down that's causing the Nitrite spike, not too sure on that one. In a cycled system it's unusual to see such high Nitrite readings with no Amm present, Nitrite usually converts very quickly.

    Hopefully it's all sorted now.
     
  11. kadarra

    kadarra New Member

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    Looks like the Nitrobacters have gone on strike or left home. I have had some high Nitrite readings for the last few days.

    For the last 3 days pH has been 6.8, ammonia at between 0.00-0.25, Nitrites initially at 0.00, then 2.0ppm and then 1.00ppm (maybe 2.0ppm) and then tonight at about 5ppm Water temps have been consistent at 14.5-15 degrees

    Fish are not being fed (and haven't for a few days when the spike first registered) and I checked the FT tonight for dead fish. I could not find any and it still looks like all 10 are there and swimming around. Its hard to do a head count when they won't stay still for more than a second so I don't think this is the issue.

    I stuck the camera in there and had a good poke around and there are a couple of gum leaves and a twig or too and some fish poo in the corners but that is it. I've uploaded it here to youtube.


    I don't know what to make of it.

    I then halved the test sample and topped with tap water (effectively diluted the water sample by half) and tested again and got almost the same result. It looks to me that the Nitrite reading looks close to 5ppm on both tests. Second photo with Nitrite test by itself is the diluted one.
    20170516_192428_resized.jpg 20170516_194154_resized.jpg 20170516_194154_resized.jpg

    I have salted to 2ppt and the fish don't seem stressed or showing any signs of distress (to me) but it worries the heck out of me. Somebody may be able tell me different from the video and let me know.

    I seem to have plenty of aeration with my backup pump running 24/7 with a spray bar and the aerator as well, along with my sump pump tank.

    Any ideas on what to do please? Do I just ride it out and pray and hope. Or do I do a partial water change. If I do this will it affect any more bacteria? I have emptied my rain tank and can probably do 150 litres of standing pumped water in 24 hrs. Either that or its straight tap water with its nasties.
     
  12. Yabbies4me

    Yabbies4me Administrator Staff Member

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    The Nitrobacter do prefer the water temp in the mid 20's and they do prefer the pH to be in the 7.5-8.0 range.

    You can't do much about the water temp unless you want to chuck a water heater into the system for a week or two, but you could kill two birds with one stone and do a couple of 25-30% water changes with aged tap water, a couple of days apart. This will reduce the Nitrite level (anything above 2.0ppm is undesirable, even if salted) and also possibly raise the pH, as most tap waters tend to be slightly alkaline.

    Short of that, you could raise the pH with some Potassium bicarbonate and Hydrated lime. If you do, add them in a 1:3 ratio, and add the carbonates first, followed by the hydroxide half an hour or so later.
    .
     
  13. kadarra

    kadarra New Member

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    Ok, I dumped 150 litres and added 150 litres of aged and bubbled tap water treated with 1500mg of vitamin c for yhe chloramines and also added 40ml of API Quickstart. Yesterday the Nitrites were trending down and theNitrates were trending up. Today that continued and this morning Nitrites and ammonia were both zero. Nitrates were up to 80ppm. So guess what - the little trout got a small feed. They smashed the sinking pellets, even grabbing them from the surface. I found a couple of grubs after the rain last night and they chomped them down too.
    Tested the water again late this afternoon and its still the same. I hope we have turned the corner. I have even turned off my 12 volt back up pump/spray bar and just using the regular pump and air pump now.
    :broc1::carrot:
     
  14. kadarra

    kadarra New Member

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    I think the problem was I added the water for a couple of the water changes through the growbeds rather than into the sump tank, and this probably took its toll on the bacteria causing the higher than expected Nitrite spike.

    The Nitrate spike was the error in following the test procedure
     

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