Tilapia Temperature.

DuiNui

I've read in many places that the ideal temp for Tilapia growth is around 28C.
I just found this:
Temperature

The recommended water temperature for tilapia is 28-30 degrees C (82-86 degrees F). The growth rate will decrease dramatically if the water is colder than 20 degrees C (50 degrees F) and fishes will normally start dying at roughly 10 degrees C (50 degrees F). It is also important to remember that cold water will affect the immune system of the fish and make it more prone to ill health. A water temperature below 13 degrees C (55 degrees F) is therefore never advisable.

at:
http://www.aquaticcommunity.com/tilapia/tankculture.php

The air temp in Chiang Mai has hit some lows this year, 10.2C is the lowest I've seen in a long time.
My water generally stays 3C or so above the air-temp low, which is putting me in the danger zone according to the above paragraph.

Anyone have any personal experience to confirm/deny the above statement?
I'm thinking about making a solar heater for this time of year, day time temps are low 30C's.

earthbound

Yeah my Tilapia died outside in winter here when the water temps got down to about 10... The problem is that even if your water is at 13-15, they really aren't going to be happy and they will be very prone to disease..

DuiNui

earthbound wrote:

they will be very prone to disease..

Hmmm that is what is worrying me.
Thanks for the reply.

Dave Donley

Dead on info, same as what I saw with them. Below 70 and they just aren't happy fish.

Ao+

my tillapia eat well at 28C -30c.

DuiNui

Thanks DD.
Continuing along the idea of solar water heating...
What would the upper limit for Tilapia (and Koi for that matter, I have some Koi in the system) be?
I'm thinking of using a coiled black poly pipe to heat the water in the day but obviously don't want it to get too hot.
Currently I have about 1500L of water in the system, so I don't think overheating will be a problem.

DuiNui

Ao+ wrote:

my tillapia eat well at 28C -30c.

Mine eat well, but are slow in the morning, maybe I need to get some coffee in the system

DuiNui

I bought 100m of LPDE pipe today to make a solar heater.
Here's a graph of Temp taken every minute.
Blue is air, Red water.
See if you can spot the point where I turned the power head on connected to the black pipe

Attachment:

Temp-23-01.png [ 4.87 KiB | Viewed 1929 times ]

DuiNui

Just had a bright idea, doesn't happen often these days.
Instead of pumping out of the FT and back into the FT, I put the end of the hot-pipe in the sump, now it just siphons to the sump

The flow has slowed without the pump in there as the drop is only about 0.5M, now the water coming out of it is almost too hot to keep your hand under it!

I know this is somewhat risky, if the main pump fails the siphon will empty the main tank.
I'll just make sure the inlet is near enough to the surface of the FT water.

DuiNui

Got the water up to 26.5C today.
Gonna have to work out some way of insulating the tanks so the swing is not so great.
Be nice to get the daytime temps up to 30C too.

Was quite windy today, I guess that explains the "noisy" air temp reading.

Attachment:

Temp-24-01.png [ 30.07 KiB | Viewed 1901 times ]

Ao+

How big is your system?
I never have that swing.

DuiNui

About 1500L.
Don't forget night time temps in Chonburi are a lot higher than Chiang Mai this time of year.
Was around 16C at 7am today.

Ao+

Hmm.. so i see your issue why you want to make the temp. sensor.

Sterfire

I was planning on making a solar heater, there are some very good designs and info at this site http://www.builditsolar.com/Projects/Wa ... eating.htm

I am in the gathering stage of building this system http://www.builditsolar.com/Experimenta ... erview.htm

I just need to grab some PEX tubing and glass ( that is the hard part to find for cheep ). I am going to make a simple circuit to control a small pump and turn it off/on when the temperature of the FT is below the temp of the heater panel for winter time, then in summer i can use it to cool the FT during the night if needed by taking off the glass and running the pump. This combined with a back up heater ( to run at night when water temps dip to lower then i want ) should save me a bit.

The only reason why i want to do something like this, is that summer is too hot for trout and winter is too cold for Tilapia.

Sterfire

Also, on a nice sunny day, you can easily reach temps to 120F in a solar powered storage tank, make this big enough and your collectors cover enough space, and you can keep that water slowly circulating in your FT to keep it warm at night.

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