Future Upgrade...need opinions please

[Modo]

Within the year I plan on upgrading my current 29g to a larger tank. Due to space constraints I am trying to decide between a 75g (48x18x20) or a 90g (48x18x24). This will be a SPS dominated tank w/ clams lit by two 250w Iwasakis with VHO actinic supplemention. I will convert my current 29g to the sump.

I guess my dilema comes between volume vs light penetration. Will the additional 4in in height drop my light intensity toward the bottom of the tank that much? Is 4in vertical going to give me that much more swimming space for fish or rock placement/growing room?

I would like to hear some opinions please. Thanks.

 

[Anonymous]

Light from a point source decreases in intensity as 1/r**2, so the bottom of the tank will be a bit less bright. For a line source (approx. by fluorescents,) it goes as 1/r, and for a plane source, (approximated by a bank of fluorescents,) it is independent of distance.)

As long as your coral of interest is the same distance from the bulb it doesn't matter. I would go for the bigger tank, all things being equal. But as you correctly note, a wider tank would be more useful than a taller one.

 

[SPC]

Posted by Modo:
Due to space constraints I am trying to decide between a 75g (48x18x20) or a 90g (48x18x24).

Modo, I presume the space constraint you are speaking of is the 48" length. If this is the case you may want to consider a 120, same as 180 only two feet shorter.
Steve

 

[Carpentersreef]

I'd just like to say how nice it is to see AOTS posting reef advice.
Maybe he will start attending church and doing some charity work on the weekends, too

)

Modo, as far as lighting, please have a serious look at the German double ended HQI's. Very intense light with pretty much no blue spectrum supplementation needed. I am presently setting up a 180g with 3 x 150w HQI's for a softie tank because the 250w hqi's are too much for them. (10k)

Mitch

[ March 09, 2002: Message edited by: Carpentersreef ]</p>

 

[smokie]

I had an all glass 90 gallon that had those exact measurements my problem wasnt getting enough lat\ight to penetrate,it was being able to reach into the tank to clean algae or move a rock or anything that required me to reach in the tank.
With the tank on its stand i had to step up on a 2 foot tall stool to reach in the tank as far as i could and i still lacked 2 inches from touching the bottom of it when my armpit bottomed out.
Needless to say i sold it shortly after getting it and replaced it with a 125 Gallon 20 inch tall tank and custom built my oak stand and hood.
IMO shorter is better.

 

[dobish]

I'm glad you asked...

From personal experience, I would recommend going with a 90 gallon over the 75...the reason I recommend this is, the 4+ inches of sand bed ends up eating up alot of water depth from the moment you start.
I also prefer to add a mix of corals - sps, lps, and softies) whose requirements range from high to medium-low light, the extra depth allows for a greater range of light distribution.
Now for the kicker - I just set up my new 75...during the set-up I kicked myself for not getting a 90!

Hope this helps,

 

[FishDaddy]

I constantly go back and forth in planning my next tank. The 55 has been great but I've got to upgrade soon.
So much depends on the amount of time and money you want to put in to the project. Bigger is certainly better but obviously, more expensive and time consuming.
A 75 is an excellent size as I can use just about everything I have in the 55. The extra room in the cabinet is a big plus for sumps, etc.
A 90 is just a deeper 75. That extra depth is more water volume but, as pointed out, 24" depth can be a problem with working on the bottom of the tank. Teh extra depth also means more lighting requirements.
Then, when considering the 90, the thought is that it's just a thicker 120, so why not??????
Finally, a 6' tank is appealing for being able to keep larger fish.
So, where does it end? Cost is a really big factor for most of us, so the 75 begins to look better all the time.

Dick

 

[smokie]

To each his own,I kicked myself for getting the 90.Oh and by the way when i got my 125 gallon i got an oceanic not another ALLGLASS.
Another thing you might consider if you going to put some sort of canopy on it for lighting such as halides ect...
A 90 Gallon looks top heavy with the canopy on it because its alreay so tall without it.Of course that my opinion.

 

[iphy]

I, too, have a 55gal. tank I want to upgrade. I've asked a few folks here "offline" about some questions I have, but now I guess I will take the plunge and post my two problems.

First, like everyone, I have special space restrictions. The entire tank with stand (and hood if it covers the whole top of the tank) can only be 50" high and 50" wide. I was thinking I could gain some volume by having a custom stand which was shorter than the usual 27" and/or by having a deeper (front to back) tank. The 55gal I have is about 13" front-to-back and I figure I could go to 18" or 20". But, now I seem to be talking about a serious custom job. Is a custom tank going to run me a lot more than just getting an 90 and a short stand (or maybe a 100 and filling the entire wall it's on, yeah, that's it)? I know it will be more to get custom, but it might be worth it....

Second, I was thinking of adding acrylic partitions to my existing 55gal. (after moving everything to the hypothetical new tank) and using it for a sump with refugium (assuming it will fit in whatever height stand I end up getting. Then I started doing the math for how much this sort of setup would weigh. When you start figuring the weight of the water/sand/rock in your tank and the weight of the tank itself and then add the weight of the sump/refugium plus the water and sand in the refugium, how do decide if it is just going to fall right through the *#$*@ floor? This is on the first floor of a house, and I see a lot of people putting sump/refugiums in their cabinets on some really big tanks. Are you all just structural engineers and you know these things?

 

[Modo]

Thanks guys for all the input so far! It sounds like this is just about the "Catch 22" we all run into when planning a system.

About my space constraint issue, I am limited in depth and length in both the room and my wallet!

I still have time before I need to make a final decision and all the input so far has got me thinking on several different issues.

I'm definately going to look into the HQI's. Anyone have any links?