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| Water temperature and salt levels http://byap.backyardmagazines.com/forum/viewtopic.php?f=1&t=5097 |
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| Author: | dbird [ Mar 15th, '09, 15:38 ] |
| Post subject: | Water temperature and salt levels |
. Often on the forum we talk about raising temperatures but how warm is too warm.In hydro they say 20 degres is the otimum temperture is this the same for AP.When you are growing barra and tilapia it would be hardly be warm enough . Also when anyone has fish problems the cure is often put salt in the water.As I have spent my life trying to keep salt out of water it seems odd.How much is too much salt for plants.I have a mildly salt streem in my back yard so if I could shandy a bit of that in it would be worth developing it. |
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| Author: | Dufflight [ Mar 15th, '09, 18:12 ] |
| Post subject: | Re: Water temerature and salt levels |
Not sure on the best temp, depends on the fish. I keep 2ppt of salt in my system all the time. The plants don't seem to mind and the fish are happy. Sea salt supplies a lot of trace for the plants also. They are even adding it to hydro and dirt gardens. |
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| Author: | creative1 [ Mar 15th, '09, 20:45 ] |
| Post subject: | Re: Water temerature and salt levels |
dbird - temps change to give optimal germination of different species... not just germination, that way we get seasonal variation for our diet. IE summer veg have much more water in them  andhelps us to ingest vital nutrients that may have been used up during the day. This is only my gathering of info over the years. So not neccesarilly fact more a feeling. C1 |
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| Author: | TCLynx [ Mar 15th, '09, 22:12 ] |
| Post subject: | Re: Water temerature and salt levels |
You are totally right that the optimum temperature and salt levels will vary depending on the situation and the fish species involved. Strawberries don't seem to like salt very much and many will say they are the first to suffer from a heavy dose of salt. Other plants don't seem to mind salt at all. Some types of tilapia can live in sea water (apparently some of the escaped tilapia from the early fish farms in Florida are happily populating Tampa Bay.) While Channel Catfish don't like more than 5 ppt of salt in their water. And then temperatures. Choosing seasonally appropriate plants is generally a good idea but keep in mind that greenhouse growing can be a whole different world, as I discovered over winter. You really must keep the fish alive and thriving so the plants will just have to deal with the water temps the fish like. Trout like cool water and tilapia/barra like warm water so there is no easy generalization that 20 C is the best temp since the trout see that as warm and the tilapia think it is chilly. However, at least most anything survives at 20 C. |
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| Author: | RupertofOZ [ Mar 15th, '09, 22:38 ] |
| Post subject: | Re: Water temerature and salt levels |
Don, generally... optimum temperatures suggested in hydro operations are related to the properties of the nutrient compound mix and the methodology of hydroponic units.... rather than actually related to any requirement or direct detrement to plant growth.... The nature of NFT equipment is such that ambient temperatures can rapidly increase within the thin film of nutrients.... which in itself can directly affect plant health by lowering available oxygen supply...but more particularly results in poor or complete lockout of essentail nutrient (trace element) uptake by the formation of "ionic salts" , and in extremes, the actual precipitation of compond "salts".... not just merely "salt" (NaCl) as such... and the effect on the osmotic balances, transfers and uptake within the plants... And indeed the measure of electrical conductivity... is a measure of these "ionic salts"... not a measure of pure salinity... It's the combination of lower oxygen availability to the root zone,trace element uptake and osmotic imbalance, that is detremental to plants in a hydroponic system.... rather than the direct influence of the nutrient temperature itself. The use of "salt" (NaCl) in an aquaponic system is directly related to affects on the internal osmotic balances within the fish (nitrite poisoning) and treatment of parasitic and some fungal infections. Most plants will suffer little affect from water temperatures that are commonly within the preferred range for optimal fish growth. Salting a system to 3ppt will have minimal affect on most plants, particularly as it's often only employed for short periods of time before dilution to lower levels. Elevated salt levels of 6ppt+, utilised for disease treatment, will impact on some plant types... particularly strawberries and cucumbers (especially those with long vine growth)... Most plants however will suffer little effect from salt levels up to 3ppt.... and (as suggested) there is a growing body of evidence that maintaining a level of salt to 2ppt... is not only beneifical for fish stock... but plant growth... particularly sea salt... |
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| Author: | dbird [ Mar 17th, '09, 20:43 ] |
| Post subject: | Re: Water temperature and salt levels |
The main purpose of my Query is that I intend keeping barra and tilapia over winter and I intend to use solar heating with electric back up.The electric is ok because I can regulate it but the solar will be a bit more hit and miss and I was wondering hot it could get. Unfortunately I know how hot it has to get to kill trout.Could taste 3ppt of salt in the water. |
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| Author: | RupertofOZ [ Mar 17th, '09, 22:53 ] |
| Post subject: | Re: Water temperature and salt levels |
Wouldn't push either fish above 30.... not completely sure of the upper tolerance for Tilapia... Remember.. the hotter the water... the lower the DO.... compensate accordingly... 
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