Placement of MH lights and chiller water return

[mv3i]

Hi guys ,

this might be a bit old stuff for you guys but would like to know the following :

(1) How high do you guys place your MH lights above the water ???

( What kind of spread are you looking for in the tank with the lights ?? )

(2) For the chiller water return , where would the most suitable position to placed them ?? ( Also, where would be the best place to put the pump for the chiller ?)

(3) What is the average usage a day for the chiller ??

( with all lights on and without ??? )

( what kinda of lights and how long you have them on )

thanks

[Tanzy]

1) About 9-10 inches above the water.

One bulb per 2 square feet.

2) In the last chamber of the sump to allow some mixing and equalisation of water temperature before being sent back up into the main tank.

Anywhere for the pump will be fine.

3) Teco RA680, 10 hrs/day to maintain 27.0C (Hysterisis 0.8C)

[mv3i]

thanks tanzy ,

just like to now something else ...

your chiller is on 10 hrs/ day and i reckon you have a 4ft tank ???

[Tanzy]

I have a 75gal 4 footer.

Heat from:

2x 400W MH no FL/PC supplement because of heat.

2x Eheim 1060 for sump return and chiller circulation.

1x Eheim 1046 for ca reactor.

1x Iwaki MD40R for skimmer.

4x Powerhead in tank.

Additional two 4" fans blowing at space between lamp and water.

[chanbi]

Tanzy, u are using such a high flow rate for the chiller? Is there any optimum flow rate into the chiller?

[mv3i]

just curious does the fan really help much in helping to cool off/ blow away someof the heat ??

[mv3i]

what kinda pump would be suitable for the chiller then ?

what kinda of flow from the chiller return are we looking at ??

i'm using the 1060 for the sump to tank return .....

[Tanzy]

chanbi,

The chiller circulation pump doubles as a backup for the sump return in case the sump return pump breaks down. That's how I lost nearly everything in my previous setup so I'm being careful this time.

mv3i,

The fans doesn't really help much but are there to increase evaporation so I can add more kalkwasser to meet the system requirement.

The flow for the chiller should be according to manufacturer recommendations.

[chanbi]

Tanzy, based on manufacturer recommendation, take for example your RA680, they only said min 400l/h?

[Tanzy]

chanbi,

Min or max 400L/hr? The flow is high, so the chiller might run more often, but water temperature is kept within a smaller range. I know it's redundant, but that's the whole idea.

[mv3i]

so is it better to have a slower pump for the chiller return ... since it will fully optimize the exchange process ??

[robe]

Nope, a high flow rate over a heat exchanger increases the efficiency of heat transfer it prevents a build up of the thermal layer over the surface that restricts heat transfer.

[mv3i]

but too fast water circulation for the chiller would not be efficient too .. izit ?

any comments .....

so what is the optimum ... what kinda of flow rate to look for ??

[Tanzy]

You will have to find a balance or optimum flow rate which is a compromise between high flow rate and heat produced/energy used by a big pump used to move that amount of water.

[chanbi]

Tanzy, can i conclude that it is better to use a high flow rate through the chiller as long as heat generated from the pump is minimum?

[Tanzy]

I think so, robe seems to suggest that too.

Like I said, the main reason for me, is that it acts as a backup for my main pump.