Interesting development

[Rumpy Pumpy]

I'd been having some problems with evaporation with my horizontal scrubber. It had been set up since the spring and had worked well but as the weather has got colder here I've been having problems with condensation at night which culminated in my getting a mild electric shock from the lights a couple of weeks ago.

So I broke it down and placed the tile screens in the sump. with three CFLs over them and a large power head circulating water around them. I wasn't expecting them to do much filtering, just to keep the screens alive while I built a new vertical scrubber to replace the sump.

Anyhow, I got busy and I wasn't able to build a new scrubber in that first week and after 7 days I had a look and found that the screens had grown as much algae in that week as they had on the old horizontal scrubber. So I tested the water, which was fine, cleaned the screens and left it another week.

Today I cleaned the screens again and there was more algae than I was getting with the old system. Tested the water again and the tests still show zero nitrate & phosphate. So I've cleaned again and left it.

The screens are completely submerged and the the only flow is being provided by the powerhead. The lights (3 x 18w CFLs) are six to ten inches away from the screens.

So I'm going to let it run and see what happens.

[SantaMonica]

Good to see it working. It makes the point that horizontals are just not that strong (which is why you need 4X the area, and 4X the wattage).

[mrbncal]

Hmmm. . . . how deep are the tiles submerged?

[Rumpy Pumpy]

Pretty deep, about 2 inches at the top and 8-ish at the bottom.

These have 2 days growth.

[sklywag]

Rump? You don't have any flow going in sump but power heads? What about display? Power heads only there too?

I recently picked up another tank that could be used as a sump and have been considering going vertical as well. But like you, lazy bones set in and nothing changes.

Water evaporation in cooler weather. There is a working theory to it. Which I guess isn't theory but factual. Had to remove some memory so I can't open more than one window. I'll be back with an article. Hopefully.

I'm back. This was brought up on a freshwater forum I visit. Interesting thing is a lot of people including me noticed it seemed evaporation was more since it cooled down. I didn't notice it last year for some reason. http://www.engineeringtoolbox.com/evapo ... d_690.html

[Rumpy Pumpy]

Rump? You don't have any flow going in sump but power heads? What about display? Power heads only there too?

One power head moving water around the tiles/screens, it's quite a big one though, not sure of the flow.

The circulation pump back from the sump blows a lot of water into the display tank, and there are 2 Koralias in there too.

Water evaporation in cooler weather. There is a working theory to it. Which I guess isn't theory but factual. Had to remove some memory so I can't open more than one window. I'll be back with an article. Hopefully.

I'm back. This was brought up on a freshwater forum I visit. Interesting thing is a lot of people including me noticed it seemed evaporation was more since it cooled down. I didn't notice it last year for some reason. http://www.engineeringtoolbox.com/evapo ... d_690.html

You'd expect more evaporation when the ambient temperature is cooler (assuming the tank water remains the same) wouldn't you?

My problem was not evaporation but condensation. The tank has a wooden hood and my original horizontal scrubber was built under it. My tank is in an area of the house which doesn't get very warm and so water was condensing on the cooler surfaces inside the hood including the light fittings. I was going to try fitting an extractor fan into the hood but decided to scrap the in hood scrubber and try something else instead.

Since I've taken the scrubber out there has been no significant condensation inside the hood.


I'm quite surprised how well the algae is growing in the sump so far. I was only expecting to keep it ticking over, what with the reduced flow and lights further away and depth of submersion.

[rygh]

Evaporation is heavily dominated by humidity, or more specifically, (Max saturated humidty - current humidity).
Warm air can hold a LOT more water than cold air, so Max humidity goes up, and evaporation goes up.
And it warms the surface a bit, but in a tank, probably irrelevant.


But back to your real thread:
1) Very interesting.
2) Did you notice any difference in the type of algae being grown?
My semi-horizontal grows a mixture of iceplant like stuff and hair. I was wondering if it is all hair.
3) You probably have far more flow than you think, and likely more than before.
A powerhead can produce way more flow than a pump.

[Rumpy Pumpy]

2) Did you notice any difference in the type of algae being grown?
My semi-horizontal grows a mixture of iceplant like stuff and hair. I was wondering if it is all hair.

Yes, the horizontal was covered in fine browny-green very fluffy stuff which could be washed/scraped off easily. Some would break off and could be seen in the display tank and the fish wouldn't eat it (I occasionally had to fish it out with a net), and there was a layer of green (and some red around the inlet) algae underneath it.

Now the brown fluffy stuff has vanished completely and it seems to be the green layer which is growing more. I wouldn't describe it as hair algae though. When I first set up the horizontal the first type of algae that grew was hair algae. That was lovely stuff! But the other types gradually took over.


3) You probably have far more flow than you think, and likely more than before.
A powerhead can produce way more flow than a pump.[/quote]

I think I was passing about 3000 litres (800 US gallons) per hour over the horizontal (eventually) which was about 5 inches wide, so there was plenty of flow. The power head in the sump is much less powerful than the return pump, but sure, there's no head to overcome.

Something I did notice though, in the first week after I moved the tiles from the horizontal to the sump, I had three of them propped up against the sides of the sump and one laying flat on the bottom. The P/H is attached to the other wall of the sump near the bottom and so it was blowing over the tile which was lying flat giving it more direct flow than the others That tile had noticeably less growth in the first week than the others. Since then I've also got that one propped up against the side and it has caught up. I guess it might be that it was getting less light due to being submerged deeper, but that said, there doesn't seem to be an noticeable difference in the algae growth on the propped up tiles between the tops and the bottoms.


I'll try to do some better pictures next time I clean it and post them up.

[Rumpy Pumpy]

Further update.

Went to clean them this afternoon and found that this weeks growth has been a lot less than before. Less than on the horizontal in fact. No idea why.

I don't think this is going to work and so I'm going to start on making a verticle now.