Backyard Aquaponics
A place to discuss aquaponics

Couple of questians on purging fish in a 300 litre tank with 3 pp salt and 4 fish how often do you need to change the water or would a good filter with a uv light do the same thing

Mon is the one but 300 ltrs should b sufficent to clenz the fish.
How long are u intending to purge for?
BTW Hi
C1

F&F - I currently have 3 good sized jade perch purging in a 150-200 litre tank with 3ppt salt. In all I would have close to 2kg of fish in the tank. They have now been there for approx 52 hours and the ammonia level is close to 2. As the pH is fairly high and I am maintaining a reasonable temp in the tank by use of a heater, that level of ammonia is far from ideal, so I will do a bit of a water change tonight.

It should be noted also that these fish were not fed for a few days before they went in the tank, so ammonia production may well be less than if they had been. Mind you the bulk of ammonia is released through the gills, not in the poo and these fish would be metabolising their huge fat stores that they have in their gut cavity.

In future, because I want to conserve water (don't want to have to do water changes) I will run a cycled biofilter on my purge tank. Because ammonia production will be relativelly low - nitrate level will not get too high during purging. At end of purging a few fish and before the next lot go in (or maybe every couple of sets dependant on nitrate level) I will use the purge tank water to top up my main system and replenish the purge tank with fresh (3ppt salted) water.

The UV filter would do nothing for you IMHO. How long do you intend purging? I'd just monitor the levels and play it by ear F&F. Remind me - are you a tester and non-tester (ie do you have a kit)?

Here is a pic - the filter had all new media so is just acting as a mechanical filter, not biofiler.

Why do you have to purge the fish?

-Stevo

Removes any off-flavours (i.e muddiness) due to the pellet feed

Also gives them a chance to clear the lines ( POO ) in case your not to good at filleting and puncture something you shouldn't

also becoming a ritual for AP... possibly a way of saying good bye...
a last wish .. to swim in clean water before my death!!

As it turns out - I do not need to purge these fish. I couldn't help myself and pulled 4 out on Sunday, eating one and putting the other 3 in the purging tank. The fish was beautiful. No feed for several days before harvest due to cold temps effectivelly was the purging. Good thing though about having these fish in the small tank is I can easilly get them out (one by one if desired) without stressing the entire population of fish.

Plus they look real good in the clear water

Do you bake yours VB?

I did the one on Sunday in alfoil under the griller (cooked it whole with a simple mix of corriander, italian parsley and a smidge of lime). Was very nice and filling. The fish was 550 grams gutted and gilled.

if you like corriander and lime then you must also like sweet chilli sauce they all go together or would if I had anything to do with it IMHO
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