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70W MH in stock Nano Cube!!


artarmon42

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I have to say, the instructions were pretty straightforward. I had no problems understanding them. The only problem I ran into (if you could call it a problem) was that I didn't know that I would also require new screws to mount the new fans as the stock screws weren't long enough. Perhaps you could mention that in the instructions so others won't be caught offguard. Fortunately I had some spare screws on me when I started.

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artarmon42

Thanks Bobbozr2.

 

I didn't recall needing any more screws, but now that you bring it up you must be right. Perhaps I used some of the screws from the extra fans I bought from nexfan ???

 

If you don't mind "improvising", I think you should also be able to use the stock/shorter screws. You just thread it through the lower mounting hole (rather than the upper and lower holes), and then use a "long" screwdriver (like those use for fixing glasses) to turn the screw into place.

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Originally posted by artarmon42

Thanks Bobbozr2.

 

I didn't recall needing any more screws, but now that you bring it up you must be right. Perhaps I used some of the screws from the extra fans I bought from nexfan ???

 

If you don't mind "improvising", I think you should also be able to use the stock/shorter screws. You just thread it through the lower mounting hole (rather than the upper and lower holes), and then use a "long" screwdriver (like those use for fixing glasses) to turn the screw into place.

 

Actually, with the fans that you linked to (the ones that I purchased, there is only one "tunnel" to send the screws threw. You need longer screws to get it to work. It's really not a big deal, but it's something you could include in your instructions.

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I just started the second photo period now. I work 12-13 hour shifts so I haven't been home all day. We'll see how the splashguard holds up. I'll run it for 3 hours if I can. I'm not worried about damaging any livestock since the tank is essentially empty...well, unless you count my abundance of pods.

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Well, I inadvertently fell asleep while performing the next photo period tonight. I intended for it to be only a 3 hour period where I would monitor the temp and the status of the splashguard, but it turned into a 6 hour photo period. I still have some data for that period though.

 

Before firing up the MH, the tank's temp (with the 13watt fuge light being on all day) was 79.2. After the 6 hour photo period, the tank's temp was 79.5. The splashguard was warm under the MH bulb, but you could easily leave your hand on the location without feeling any discomfort. The splashguard/hood showed no signs of warping. I also noticed that during yesterday and today's photo period (2 and 6 hours respectively, the voltage of the hood's fans (not the rear scroll fan) were set at 6v instead of 7.5v. With the temps being so steady after a 6 hour period with no signs of fatigue on the splashguard/hood, I have concluded that I don't need to set my hood's fans at 7.5v, thus eliminating some of the noise. The rear scroll fan is set to 7.5v during MH operation.

 

It appears that the rear scroll fan's power of evaporative cooling is the real hero in this mod. With the hood fans at 6v (keeping in mind that there are only 3 of the larger profile fans [as opposed to 4] and 1 stock fan operating to cool off the inside of the hood) the hood is more than sufficiently cooled; at least for me. I'm sure each application varies. I haven't noticed all that much evaporation either. I may have to top off the tank today with a little RO, but it appears to be a minute amount if any. So far I'm more than impressed at how successful this mod has been.

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artarmon42

Just out of curiousity, are you seeing much visual effect from that actinic (besides dawn/dusk effects)? With the MH on, does the 20k over power the actinic? If you were to switch off the actinic, would you notice anything?

 

Thanks for the update on the voltage decrease. I'll let you proof 6v for the full 8 hour first and then make the change myself ;)

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Originally posted by artarmon42

Just out of curiousity, are you seeing much visual effect from that actinic (besides dawn/dusk effects)? With the MH on, does the 20k over power the actinic? If you were to switch off the actinic, would you notice anything?

 

Thanks for the update on the voltage decrease. I'll let you proof 6v for the full 8 hour first and then make the change myself ;)

 

I don't see much, if any visual effect from the actinic. It really wasn't my intention in the first place. It's there to provide for the dawn/dusk effect. The MH is just way too overpowering to notice, and at 20k I suspect it would be hard to notice even if it was provided by a series of T5's. I may upgrade to a couple of T5's in the future, but I don't think they're really necessary with the 20k.

 

I started today's photo period. I'm going to try and run it over 8 hours just to see what it can do. I'm that confident in the fan setup at this point since it worked flawlessly last night as I accidently fell asleep. zzz Tonight the tank's temp before the photo period and with just the 13watt actinic on all day for 13+ hours, was 79.8. Not even 3 minutes from when I turned it on the temp was 79.5. I'm not only running the MH, but I'm also running the 13w fuge and the 13w actinic. This would simulate my setup during peak photo period hours on any given day from here on out. This is the real test, but I suspect that it will hold up. I'll post my findings for you tomorrow.

 

BTW, nice looking tank. The updated pics look great. I can't wait to get my sps tank up and running. Hell, it's been cycling for almost 3 weeks now and I have yet to test for ammonia, nitrites, nitrates. :P I've been so preoccupied with the mod that I haven't got the itch to stock it yet. Judging by the way my pods are flourishing, I suspect things are doing alright.

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artarmon42
Originally posted by Bobbozr2

Tonight the tank's temp before the photo period and with just the 13watt actinic on all day for 13+ hours, was 79.8. Not even 3 minutes from when I turned it on the temp was 79.5. I'm not only running the MH, but I'm also running the 13w fuge and the 13w actinic. This would simulate my setup during peak photo period hours on any given day from here on out. This is the real test, but I suspect that it will hold up. I'll post my findings for you tomorrow.

 

Looking forward to the results.

 

I'm not sure if you will only run your photo period during the evening/night. If you will ever run it during the day (which means hotter ambient temps), you should run that test.

 

In the last week, I've actually played with the voltage of the rear scroll fan. I've dropped the voltage from 7.5V to 6V, without any impact to the cooling of the system (but now there's even less top off required).

 

I couldn't resist, and dropped the hood fan voltages to 6V like you. Running my normal 8 hour photo period, everything looks good! Will check the splashguard over the next few days to make sure everything remains good.

 

 

 

Wonder if Sterling or anyone else has tried to do this mod yet ???

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artarmon42
Originally posted by Chronicles

Hey, in general what would you say puts out more heat, a 96w power quad or 70w mh?

 

"Pound for pound", I'd say the 70W MH puts out more heat.

 

But you then have to consider that the power quad is going to sit in the reflector, and you'll be limited to the stock fan positions. Whereas, this mod removes the reflector (getting better airflow ;)) and adds more fans (getting more CFM :P).

 

Which one has a cooler hood? Undoubtedly, the 70W MH mod B)

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I'm going to eventually run the photo period during the day, but I've been working 13 hour shifts since I completed the mod. I leave the house at 6am and don't get home until after 8pm. I don't want to run the test when I'm not home. I'm off again this Thursday so I'll run a photo period during the day at that time.

 

Yeah, I'm kind of wondering if anyone else has done this mod. I see the thread for the nano chiller and I can't help but think your way is the much cheaper and efficient solution. ;)

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artarmon42
Originally posted by Bobbozr2

I see the thread for the nano chiller and I can't help but think your way is the much cheaper and efficient solution. ;)

 

For sure the chiller is a more powerful solution.

 

But in my situation (which I think is pretty common), my ambient temperature will never get above 85F at most. I just need a solution that maintain the tank temperature at most 2-3 degrees below ambient, and I think this is an easy and cheap way to meet that requirement.

 

If you do a search on reefcentral, every summer people discuss methods of cooling their tanks. Using fan driven evaporative cooling, people have achieved up to 7-8 degree decrease from ambient.

 

So far, 6V looks to be able to compensate for MH heat, plus maintain at least 2 degrees below ambient. Of course summer will tell whether this solution is capable enough (when ambient is higher than the tank temperature). So far, I've only had one day where the ambient was 82 while the tank (with MH on) was able to maintain the temps just over 80.

 

I presume with a higher voltage should be able to sustain a bigger decrease from ambient. I will probably just set the voltage higher as an insurance policy, when summer rolls around and just live witht the evaporation. Time will tell.

 

 

 

But I certainly wouldn't knock the chiller idea. If people keep their tanks in hot houses (or perhaps in uninstalted places such as garages), the chiller might be the only solution.

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Well, the 9 hour photo period is up. The tank's ending temp is 79.5 (starting temp was 79.4). The splashguard held up. It was warm, but not hot and showed no signs of warping. I know that this was done at night with lower ambient temps (I live in NJ) so I have to see how it handles the higher daytime temps. I'll keep you posted.

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artarmon42

Any updates bobozr2?

Anyone else going to attempt this?

 

Looks like summer is coming, so I've stuck my min/max thermometer back in to see how this mod holds up. I'll report back once I get a few days of measurements.

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Well, I started running the MH at 3pm EST today. I didn't get a chance to measure the ambient temp in the house/room at the time(I was going to, but I discovered a termite situation...long story) but the outside air temp was 75 degrees and the room was probably around 75 or so as well (perhaps more with the sun coming in the sunroom, adjacent to the kitchen area where the tank is). Before the photo period, the tank temp was 79.8. The current tank temp after an 8 hour photo period is 80.5. As I was in the sunroom working on the termite situation, I saw the tank's temp spike at around 80.8/80.9. I never saw it break 81.

 

So, after an 8 hour photo period, with higher ambient temps, the temperature only rose around 1 degree at it's highest point. In the summer, I run the air conditioning at around 70 or so so I don't think temps should be a problem. As a last resort, I could always raise the voltage of the rear scroll fan to compensate. It's currently only at 7.5v.

 

The splashguard remains intact with no signs of warping as well. So far so good. I'll try and run another daytime test on my next day off. Hopefully it'll be a bit warmer in the house. Perhaps I'll turn on the heat in the house and see. ;) I don't have any livestock in the tank yet, but I tested my water perams and they seem ready to go for a cleanup crew. Besides, with all this MH testing going on, I accelerated my inevitable diatom bloom. :(

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artarmon42
Originally posted by Bobbozr2

Before the photo period, the tank temp was 79.8. The current tank temp after an 8 hour photo period is 80.5. As I was in the sunroom working on the termite situation, I saw the tank's temp spike at around 80.8/80.9.  

 

So the tank temp went up and then down during your photo period? Any idea what caused it to go up in the first place?

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lucubrator

artarmon - You state in the beginning of the thread that blowers are more powerful at pushing air than are axial fans, I wondered where you got this information.

From sunon's website: blower vs. axial, comparing the 120mm fans at the end of the pdf:

pmb1212plb2-A is a 9.8w blower pushing 35.9 cfm, where the

pdm1212ptb2-A is an 8.4w axial pushing 133 cfm. So is it the static pressure difference that you're going for? (.89 v. .50 inch-H2O, respectively)

Thanks

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artarmon42
Originally posted by lucubrator

artarmon - You state in the beginning of the thread that blowers are more powerful at pushing air than are axial fans, I wondered where you got this information.  

 

Sorry for the confusion.

 

At the start of the thread, I was not using pure CFM as the definition of "powerful". Because I was trying to blow air "further", the distance that the air would travel was used as my definition of "power". Blowers by their design push air further (great for trying to push the cold air further into the light chamber, great for exhausting air out the side vents so it doesn't get sucked back in) but do it using less air and pushing that smaller volume through a concentrated stream. That's why the scroll-fan design is used for leaf blowers.

 

Later Chronicles (another free plug for the "master of cool" :-*) suggested to try using fans that simply pushed more air around (higher CFM). My first thought was that without being able to exhaust the hot air far enough out of the cube, it would get sucked back into the system by normal aerodynamics (blow air out, something has to fill its place). Turned out I hadn't considered simple thermodynamics (hot air will mixed quickly and any that gets sucked back in would be much cooler, and eventually the area around the exhaust ports would stabilize to the cooler air) or even simpler :rolleyes: thermodynamics (even hot air blowing over anything will cool it through movement (which incidentally is the basis of the rear vent/fan technique that is fundamental to cooling the water)).

 

This is probably more data than you wanted, but I figured I'd share the thought process in the design.

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Originally posted by artarmon42

So the tank temp went up and then down during your photo period? Any idea what caused it to go up in the first place?

 

I attribute the rise in temperature to the fact that I ran the test during the day/afternoon when the ambient temp in the house was greater than 75 degrees. I previously ran the tests at night so the ambient was probably in the high 60's. The temp spike probably happened in the early afternoon when it was the hottest. As the sun went down and the ambient temp in the house went down, so did the tank's overall temp. I'll continue to run tests during various times of the day to confirm this.

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artarmon42

Do you also get (direct) sunlight on your tank?

 

Remember when I first measure the cooling effects of the rear vent/fan, it would keep the temp stable for the first few hours and then drop the temp during the last few hours of the photo period? I didn't realize it at the time, but that was because I was getting direct sunlight on the back of my tank.

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No, I don't get any direct sunlight on the tank. A window is perhaps about 2 feet away from it with a northwestern exposure. Sun may come in the window during the afternoon, but it doesn't hit the tank directly. However, it may heat the adjacent room just enough to raise ambient temps a bit. I'm not too concerned at this point. As I said, I don't keep the house all that hot during the summer. I like to keep temps around 70 or so for my personal comfort. The tank should be fine; and again, if need be, I'll just increase the voltage of the rear scroll fan.

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artarmon42

With summer coming on, I put back my min/max digital thermometer probe and get some measurements.

 

Thursday:

* Ambient Temp: 70.3 to 80.8 (10.5 variance)

* Water Temp: 79.4 to 81.0 (1.6 variance)

 

Friday:

* Ambient Temp: 72.0 to 80.4 (8.4 variance)

* Water Temp: 79.4 to 81.0 (1.6 variance)

 

Both days, the whole-house A/C kicked in ~80F (as it is set).

Both days, the water temperature only increased by 1.6 degrees.

Interestingly, it is unchanged from measurements taken last month with cooler ambients.

 

Over the weekend, when I'm home, I will experiment with higher ambients (by setting the A/C to come on at a higher temperature).

 

 

ps: For full disclosure, the low water temp recoded on my thermometer is actually ~78.4. But as I've stated previously, when the temperature actually hits that level, my heater kicks in and bumps the temp up to ~79.8. I've used 79.4 as the "low" simply because that is the water temperature for at least an hour prior to the start of the photo period. How long my heater lets the temperature get to before kicking in is a factor of the heater and outside the scope of what I'm trying to measure.

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