Backyard Aquaponics
A place to discuss aquaponics

Hi All, at last I will be getting my fingerling Rainbow trout next week for my now cycled system.

Questions;
1. How much salt is required per 1000lt of water for optimum fish health.

2. Is there some way that one can determine how much oxygen is present in the water without having expensive equipment total water in my system = 4000lts, fish tank = 2,400lts, quantity of fish 75.
Flood and drain type system 15 on 45 off usually shut down during the night hours to conserve heat.
Not turning over the fish tank water every hour probably closer to 1.5/1.75 hrs.
All help is greately appreciated.

pat from Eire

Most people shoot for about 2 ppt, the range is from 1-3 ppt, so if your measurements are not precise, 2 ppt I'd a nice target. As for DO, I don't know of a way, but you can never have too much! Air pumps are cheap to buy and run. It might be wise to add it if you are not going to turn over your FT volume every hour.

You should keep a DO level above 4 or 5mg/L to maintain fish health. This equates to approx 15-20L/min per 1000L of water assuming you are turning your water volume over approx once per hour.

Hi All re salt does 2PPT = 2kg per 1000lt of water.

thank you

pat

You got it Pat...

Thank you

When adding air to the fish tank should the air hose outlet be at the bottom of the tank??

Sorry all another question can you recomend a specific type of air pump and how much should they cost

Unless you are going to get really technical then yes always on the bottom.

Does the 2ppt salt level apply to all fish species or just trout?

Keep in mind that air flow will be lower at greater depths. Most air pumps only deliver a low pressure, for example, a 10kPa pump will not deliver any air below 1m depth. Even at 0.5m, flow will be greatly reduced from the max air flow at zero depth.

Hi All re air pump my FT is 1.3m deep and I need an air flow rate of 30 to 40lt/min should the pump that I choose have a flow rate of 80 or 120 lt/min to compensate for the depth. the pumps that I have seen are in lt's/hr instead of psi or kpa, could you suggest any specific model as I will have to bring this in from the UK and had better spec the right pump now before its too late and waste money

Thank's for all the help

pat

Comment from Charlie re salt Quote;
In regards to the salt, and in addition to sleepes comments..
Salting serves a few purposes within AP. Salting is not a necessity and there is many members that dont use it at all but it can assist in fish health.

Some fish like barra and trout have an internal salt content and when they are kept in fresh water they burn energy through osmosis to stabilise between the internal salt content and the outside water. Introducing salt limits this transfer thus saving valuable energy that is better used in fighting disease and promotes good health.

Salt assists with the slimey protective coating on the suface of the fish.

Salt can mitigate the effects of toxins like nitrite.

Salt can assist with parasitic and infection issues

Nice quote vegipat..