water temp & mh lighting
 

hi, i've just setup my new mh lighting about 8" from the top of the tank to the bottom of the light fixture. the water temp has risen 2-3degrees in 6 hours.
should the light be higher? or is it ok for the temp to go up a bit?

do you have any fans?....I am running 4 250's in an enclosed hood...installed 4 PC fans and it made a huge difference

the setup i hung up is pendant setup, not enclosed. there is 8 inches of open space between the tank and the light.

That's a huge increase in 6 hours, especially since it's not enclosed and is so high off the tank. Is this set up in a smallish room where room temps might be rising as well?

I have mine setup somewhat simmiliar and my tank temp increases about 3 degree's but I have found out that th reason my temp goes up so much is that my heater for whatever reason turns on every so often and heat the water even though it shouldn't...I solved my problem by unplugging my heater when my hallide is on and now my tank temp doesn't increase at all!!!

the room is about 9x12, in the basement of our home.
thinking about it, it's probably the floating glass thermometer thats giving the reading of the water at the top only.
do those stick on type thermometers work? any suggestions?

I love my 15$ Coralife digital thermometer. Probe can be placed anywhere in the tank. Mine is low and to the opposite side of the heater.

gotta get me one of those :smile:

Not to sound rude just for some info
I was shopping around for a digital thermometer I seen the Coralife everywhere (AI, Big Als) for around $15 and one day we were at Petsmart and they have them for $5.99 so I grabbed a couple. I have since been to 2 more Petsmarts and their regular price is $5.99 if your looking for one.

They work great I have a glass thermometer in the big tank and a coral life digital thermometer in my sump and they both read the same!!!

Me too, it's great.

When my MH's are on during the day, by the time they go off the water is at 84F. I need to get a proper canopy and fans.

Fans
 

should be considered in two places
1) for your canopy to dissipate the immediate heated air around the halide bulbs and removal of the heated air out of your canopy away from your water

2) fan aimed at the water because the process of evaporation uses up a lot of energy (consumption of energy required to bring a liquid to a higher state [in this case vapor] is significantly higher). as more water is evaporated, it consumes more heat (energy) which brings the water temp down. I have a small 4" fan that maintained my 250 gallon system at 81 F over the summer. this was before I installed the MHs but nevertheless, it was at least 88-90F for many days in the summer and my tank kept its cool around 81. :cool:

hth
cwlee

i have 2 digitals, 1 glass and 1 controller and they all give me a diffrent reading.