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Hi everyone, the system has been running for 5 weeks now its a 1000 Ltr fish tank and 4 x 250 Ltr grow beds planted with seedlings of lettuce, bok choy, kohlrabi, celery, leeks and a lot of seeded plants such as peas which are 5" tall now with radish, beetroot, spinach, carrots, coriander and parsnips.  The weather here is quite cool water temp about 14c.  We started out with 15 goldfish and now have only 7 left (I think I may have fed them too much in the early days).  My water test results today are:-

PH  7.6

Ammonia 0

Nitrite 1.0

Nitrate 10

I have been feeding the fish very lightly, I added 5mls of Hydrochloric acid yesterday to try to lower the PH which has not fallen below 7.6 right from the start.  I  have not added Seasol for 2 weeks and I am concerned about my plant health.

I would welcome your comments and/or advice.  I am hoping that the system will be cycled soon so that I can put in some Silver Perch or Trout.





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Your nitrite is a bit high but other than that I wouldn't worry too much.  1 ppt of the cheapest pool salt dissolved before adding to the system could help protect fish from the nitrite along with extra aeration.

Is your system a timed flood and drain or siphon system?  If it's a timed flood and drain you may finish up cycling quicker if you run more cycles or perhaps even run constant flood for a while.


I wouldn't stress too much about a pH of 7.6 (I've been running a system that rarely drops below that since spring of 2008 and it still grows lots of food.)  To more safely adjust your pH you might do better to adjust the top up water before adding it to the system.

Thank you for your reply, the system is a siphon system.  Do you think I can safely add some Seasol (seaweed extract) yet?

Forgive my ignorance your suggested 1 ppt of pool salt.  What does this measurement represent?


ppt = parts per thousand  ( 1 part salt to 1 thousand parts water)


You should be fine adding Seasol right now.  Your water temp is almost certainly the main cause of the slow cycle.  At that temp you can only feed goldfish a little, once a week would be ok


 My pH was 7.9 2 weeks ago, now at 6.8 and plants are showing a night and day difference.  In an old system it probably doesnt matter as much, but there is a pH range plants prefer


I dropped my pH too fast on accident a few times (like .4 in a single day) and didnt lose a fish.  But don't add pH down straight into the fish tank without diluting it.  Im not saying dropping it that much is ok, but it wasnt lethal for my fsh


Enjoy the journey!

Small amounts of seasol are fine.  (But you don't need to be adding large amounts daily, nor should you be adding it based on the number of gallons of water in your system.)  I think most people use a cap full per grow bed or something like that or with Maxicrop I would add about an ounce per grow bed.



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