Acute toxicity and sublethal effects of ammonia and nitrite for juvenile cobia

[Jonty]

Hi all,

Just a link to Sciencedirect regarding tests done on juvenile cobia of the effects of ammonia and nitrite. The amount of nitrite needed to kill 30% of the cobia is interesting. Cobia are a saltwater fish.

http://www.sciencedirect.com/science...a989bd9cc30257

As aquaponics mature and more research is carried out, some of our procedures, testing practices and ideas will be endorsed whilst others will be discarded. I have already disproved the theory that we need a pH higher than 7 for proper bacterial growth.

Regards
Jonty

[fishfood]

Hi all,

Just a link to Sciencedirect regarding tests done on juvenile cobia of the effects of ammonia and nitrite. The amount of nitrite needed to kill 30% of the cobia is interesting. Cobia are a saltwater fish.

http://www.sciencedirect.com/science...a989bd9cc30257

As aquaponics mature and more research is carried out, some of our procedures, testing practices and ideas will be endorsed whilst others will be discarded. I have already disproved the theory that we need a pH higher than 7 for proper bacterial growth.

Regards
Jonty

Yes my ph is always closer to 6 than 7 and there aint aney thing wrong with the growth in my system

[Jonty]

Hi fishfood,

The great thing about a lower pH is that excess ammonia will not harm the fish. At 28 degrees, an ammonia reading of 5, the free ammonia that is detrimental to the fish is zero. Great safety margin.

Regards
Jonty

[Hamish]

Hi fishfood,

The great thing about a lower pH is that excess ammonia will not harm the fish. At 28 degrees, an ammonia reading of 5, the free ammonia that is detrimental to the fish is zero. Great safety margin.

Regards
Jonty

Damn - just wne I get my system buffered with shell grit to around the mid 7's you tell me this!

[Jonty]

Hamish,
If you fish are doing well at your pH, leave it as is. Over the years I have seen people kill more fish with pH and temperature swings than problems associated with ammonia.

pH is mostly determined by the growbed media. I find blue metal to have a high pH whilst I am using a fruit salad stone which has a pH around 6.

My only problem is that I didn't wash the gravel in one of the growbeds. The last lot of rain has muddied the waters - literally. When I get the murray cod settled I intend to shut down the growbed and get down and dirty to get it clean.

Regards
Jonty

[Hamish]

Thanks for the info Jonty. What is a fruit salad stone?

[Murray]

Re grow bed media. I am running drainage gravel in 2 systems and clay pebbles in 2 systems and the pH is always 1 lower in the clay pebble systems.
I have not done anything to adjust pH to any of the systems once they had cycled. It is one aspect of Aquaponics I find to be amazing...how the pH just finds it's own level and just stays there.....well, that's what happens at my place

[Hamish]

I noticed my clay ball media system started at around 7.8pH and then dropped down to 6pH within a couple of weeks. I then added a mesh bag of shell grit to the grow bed (since moved to the canister filter) which has steadied the pH around the 7.4 mark. Probably should not have bothered with the shell grit - however it has not been a bother to do and very cheap. I have been reading that the calcium the shells give off is of benefit to fish health - so probably not a bad thing to do anyway.

http://www.americanaquariumproducts.com/AquariumKH.html

[Jonty]

Hamish,

Here is a shot of the fruit salad stone. Haven't got a clue what the makeup of it is.

Regards
Jonty

[Jim Bedford]

Does anyone use scoria?
I was under the impression that it was good, once washed, because of the large surface area the dimpling offers for nitrosomonas and nitrobacter habitat.
Jim B