Safe temp swings with chiller?

[jessezm]

Question for the masses/experts:

I recently plumbed in my chiller to my frag tank (about 65 total gallons) since the basement was getting a bit warm and temps were climbing into the 80s. Originally I was using the chiller's controller only, but it has too wide a margin of error for when it kicks on and off for my taste. Chiller is a JBJ commercial 1/2 hp, so it's oversized at the moment but I'm adding a DT to the system eventually and will need it then.

Annnnyyyyways, now I have it hooked up to my Apex, set to come on at 80 and off at 79. the resulting chart looks like this:

Tank takes about 1.5 - 2 hrs to climb one degree to 80, then 10 minutes to go back down to 78.7 or so.

My question is, is this too drastic/too fast a swing? And if so, should I flow more water through the chiller, and tighten the controlled parameters so it's kicking on every 30 minutes to an hr?

I'm trying to avoid too much cycling on/off, but most important is the health of my corals, which are majority SPS

I could also look into plumbing pumps externally to reduce heat transfer. I have one MJ1200 feeding some reactors and my return is a DC 10500 reef octopus diablo (on about 50% power)

Should I post this in a different forum as well?

Thanks!

 

[jda]

That looks Ok to me. If you want to slow it down, run a fan over the top of the tank... this will stretch your 2 hour climb more like 4 or 6 hours.

IMO, a 1 degree bounce more often is better than a 2 degree bounce less often.

 

[jessezm]

Kinda what I was thinking, and I like the fan idea - I actually went to three stores to buy one but keep being disappointed in the low quality and walking away... I'll pick one up this weekend.

 

[Ocelaris]

A degree difference isn't a big deal. I've snorkeled in water that was drastically different with currents. I wouldn't lower the flow through the chiller as it needs a specific minimum flow, and you'd be wasting energy cycling it longer as it'd still take the same time to rise. 10 minutes isn't short cycling imo. Here's mine over about a day.

 

[jda]

I use Vornado fans. Computer fans are like throwing a golf ball into a freight train. They are not the cheapest, but I have some that might be a decade old.

 

[jessezm]

Thanks, all. A follow up: for an SPS-dominant tank, do you think my temps are too high? I'm looking at Ocelaris' temps and they are several degrees cooler than mine. I'm coming back to the hobby after a 10-yr hiatus and catching back up a bit. I remember it was always 78 - 82 that was the rule of thumb... Shoot I be targeting lower? and why?

 

[Ocelaris]

Sorry, mine is not bit cool due to my acanthophyllia and some other lps which like it cooler. My main heat source is my 40w uv which goes 24x7. If I take that offline I use the chiller maybe four times a day. Energy in, energy out.

I used a cheapo clip on fan and got 6+months on it then got the chiller. Saltwater is highly corrosive, so I didn't think the value was there (or space).