Coldwater system

[skylsdale]

So, a couple months ago I picked this up in a "FREE" pile at a local yard sale:

Here's an actual description of the system. The only thing missing is a recirculating pump, but the refridgeration system still works like a champ, so I got my money's worth with that alone. There is some rust, as you can see in the below photo, which I'll need to clean up--I have no idea how long this was just sitting around in someone's garage or shop.

Anyway, it's got a little fixing up to do, but the main components are up and running. One of the outer panes of glass is cracked on one side, but I'm going to test it to see if it affects condensation (each side is double-paned to create a cold layer of insulating air, preventing condensation on the outer glass) or if it's just cosmetic.

My thought it to put together a little native PNW rockpool tank, but I've got a couple questions for you guys:

- Measuring water parameters. I know must hydrometers are rated to function within a certain temperature range, much higher than what I'd be dealing with. Would a refractometer work in this instance...or are they calibrated for tropical temps as well? I was thinking I could mix salt and test it at higher temps, and then let it cool before I do a water change. Would test kits be affected?

- There is some noticeable rust in places on the tank, especially the frame. I plan on getting rid of this as much as possible, and possibly repainting the entire frame with a black Rustoleam spray paint. However, I read in an older article a while back by Fenner that in his experience, colder water organisms tend to be more sensitive to metal toxicity in the water...but wasn't sure why. Anyone have any thoughts/experiences with this?

Thanks!

 

[Fatal Morgana]

>... I was thinking I could mix salt and test it at higher temps, and then let it cool before I do a water change. Would test kits be affected?
...

That will work. You are not going to do testing in a refrigrated room anyway, so just do the measurement in room temp.

 

[Anonymous]

Salinity test will be affected.

 

[skylsdale]

Seamaiden, are you saying that even a refractometer will be affected?

 

[K]

Refractometers that I have used can normally be calibrated. So just use water of the same temp, ie cold water when calibrating it and it should waork fine.
Anyway anything from a rockpool will be adapted to variations in salinity & temperature

 

[Anonymous]

and putting together a nice little Puget Sound system.

I SOOOOO wanna do this! You absolutely are required to provide pics How ya gonna get the livestock, straight from the sound?

Thanks again for the headsup on this thread

 

[skylsdale]

Yeah, I plan on getting livestock and everything straight from around the Sound. It won't be anything huge as far as livestock (some of the really cool things you would need to dive to collect, but they wouldn't be well-suited to this shallow type system, anyway). Mostly the little organisms you find in the rock and tidepools: algae, various crabs, sculpins, small anemones, etc.

 

[Anonymous]

I'm planning a cold water tank as well, but it won't be for another 4 years or so, in my next house. It will be a custom tidepool system, complete with surge device. 8)
Keep us posted skylsdale.

Jim

 

[Anonymous]

Sky, just grab some water from the ocean to calibrate your refractometer. Test the temp of the water at the same time. It doesn't really matter what the exact number is that your meter measures, as long as you keep it the same in your tank. Same goes for temp, obviously.

 

[Anonymous]

Shorecrabs, anemones, cucumbers. The possibilities are nearly endless, and easy to gather from tidepools.

:envy:

 

[Anonymous]

Shorecrabs, anemones, cucumbers. The possibilities are nearly endless, and easy to gather from tidepools.

:envy:

Limpets, chitons, abalone, urchins, sculpins, brittle stars, hermits, snails...so many little critters. I live near Monterey too, which is a great spot to collect.

 

[skylsdale]

There really is a TON of stuff that can be found in just tiny little pools. Actually, the sheer growth of coralline in some of those pools can be pretty impressive!

 

[Anonymous]

There was a great little tidepool in Bodega bay that I used to love visiting and watching. It was about the size of a 20 gallon tank, and completely covered with Anthopleura elegantissima anemones. They have beautiful colors in the sunlight. The pool also had several baby sculpins of different colors. They would deftly dart in between the tentacles and somehow avoid getting caught.

 

[skylsdale]

Alright, I have a question or two for you guys. The problem is, the pump is missing to this system as well as the manual, so I don't know exactly what the intention was with the plumbing and whatnot. On a scientific resources supply website, it mentions that "Circulation is controlled to 400 gph, aeration is in 12 constant flow aeration streams...."

Below is a quick rundown of the existing plumbing (viewed from the back of the tank). On either side are the overflow towers. These are connected and then drawn in through the pump. Now, based on the description above, I assume the other "T" in the plumbing is the outflow from the pump, and the water is intended to then fill up the central reservoir where the cooling coils are housed. From here, the water then fills that reservoir and then spills out of the 12 holes at the top of the acrylic partition. Now, on the other side of each pair of holes is an acrylic tube with a slit cut into the bottom. I assume the water is supposed to spill out of the pair of holes, into the pipe, and then pressure forces the water out of the bottom. One problem I see is that right in the bottom-center of the acrylic wall is a large hole. Any ideas on this?

Now, One of my thoughts was to just get some plastic mesh screen and cover the larger hole to prevent animals from creeping into the reservoir. This would also allow flow through. I was then thinking of plumbing a small closed loop and SCWD into the acrylic wall, with two outputs on either side by the overflow towers. This could help recreate a little wave action. I could then place a powerhead in a corner to come on a couple times a day to simulate tidal flow...or vice-versa (powerhead always on; SCWD/loop only comes on a couple times a day).

Thoughts? Ideas? Theories?

 

[Anonymous]

hmmm. Seems to me that tidepools have little to no flow for 6 to 8 hours a day. I think it may be a trial and error kinda thing. There are some biologists and biology students that I hope may chime in here to get you an idea of what ideal flow would be in nature.

 

[skylsdale]

I was thinking about that, too. I'm so used to trying to get as much flow as possible in a reef tank, that I realized I really need to look at this from a different perspective. I was most worried about oxygen levels, but then realized that since the water will be so much cooler, the oxygen levels are going to be much higher than in a similarly run tropical system. However, I don't think it would be good to have the water column be too still.

I was just looking around, and thought I would use an Eheim 1250 (317 gph) or Quiet One 1200 (296 gph) for the recirculating pump. Hopefully this would create a nice gentle flow (which there needs to be some of to promote oxygen, etc. Maybe I could then just have the SCWD come on a couple times a day to simulate some tidal action.

Thoughts?

 

[Anonymous]

The proper amount of flow or water movement really depends on what environment you're trying to recreate. Low intertidal environments are VERY turbid, high energy, and the water exchange is constant. Mid intertidal, water exchange is intermittent, but high energy. High intertidal, water is exchange happens less often, and there is less energy. That being said, almost any organism from the various microhabitats will live just fine in a tank with whatever water flow regine you decide on I'm sure. It's really not that critical. If there are any known exceptions ( an organims that needs an extremely high disolved oxygen level for instance) perhaps Matt can point that critter out.

 

[Anonymous]

What an odd setup. Sky, if you haven't already I would consider replacing that coil and somehow getting all that rust out of there. They also sell chemical resins that will 'soak up' copper in solution just in case you have any in the walls of your tank. Actually I would salvage the chiller and just buy a whole new tank, but that's me. The look of that tank scares me

Anyway, you should be fine with the flow you're talking about. The organisms are mostly very adaptable. It would help to know what types of critters you want to keep though. It should be a fairly simple task to go down to the tidepools, see a good assemblage of what you like at low tide, and then stick around for high tide to see how the current is in that area. As Jim pointed out there's a vertical gradient, but there's a horizontal one too. The stuff that gets hit with the hardest waves is usually just mussel colonies and tough kelps. You've probably seen the little palm tree looking kelps up there, Postelsia spp.; those get hit with the brunt of the incoming waves, and would probably be real hard to keep. A little closer to shore you get a more diverse array, more soft bodied stuff like anemones, etc.

Anyway, I think doing reef type wave action would be approriate.

 

[skylsdale]

Thanks, Matt. I know what you're saying about the rust, and I'm not quite sure why there seems to be so much of it, especially on the acrylic and whatnot. I think it just sat around in someone's garage or shop (when I picked it up from the yardsale, the guy was using it to hold random bolts, screws, and tools). Do you have any suggestions as to where I can find some of that copper soaking solution?

I would ditch the tank and get a new one, but that would pretty much eliminate the option of setting this thing up (just not in the budgetary cards right now). I LOVE the shallow and wide dimensions of this thing, and the double-paned glass panels will be great for preventing condensation. I think I'm going to try at least cleaning it up a bit and see how that goes...then decide whether or not it's a project I want to undertake.

The coating on the frame is supposedly baked on there (according to the website I mentioned above). However, it seems as though some of it has eroded off a bit, which has caused a little rusting. What's your opinion on using some sort of Rustoleum type spraypaint to coat the frame? The way the tank is set up, there shouldn't really be any direct contact between water and the frame, so it would just be to help cover up exposed areas and prevent further corrosion. What do you think?

 

[Anonymous]

Sounds like it would work. I haven't used the copper stuff in ages, but I found it at a LFS. Try googling "copper removes resin" maybe?