Water turnover

[Sco453]

Hi all

Getting back into the tank after a few years away from my passion.

Good times, my partner wants to renovate the house and add an extension (there had do be some kind of trade off right???? )

Okay, heres some queries which I've been trawling through the web looking for hints and clues on-

Aquaria will be 250cm x 100 cm x 130 cm (approx 3250 litres) with a 400 litre sump. South American tropical set up.

Weir over flow feed to sump and pump return

5 chambers in sump-

1. Inlet with foam
2. Bio balls
3. Alfagrog
4. Charcoal & filter wool
5. Pump chamber

Various ideas out there on 'turnover' of water in a system this size from 1/2 tank per hour to 7 tanks per hour. Even ig I go for two changes in an hour I'm still look at a 8000 litre per hour pump which just fits in last chamber in sump (although I can have the sump built differently)

Thoughts and opinions appreciated!!!!!!

Sco

 

[jsoong]

I have ~ 10x per hour in mine. Pump is rated 1070 gph (~ 4000 l/hr) or so & is fairly compact.

10x is what reef tanks are supposed to run at & many goldfish people do that as well. <Koi people also have that kind of flow rate in their ponds.> It is prob overkill for FW, and many suggests 5x is perfectly fine ... but then , no harm in a bit of redundancy (apart from electricity cost.)

Now, I don't know if this scales up to huge system like yours (almost 1000 gal). But I suspect that more is better, up to a point. With big systems, people generally don't use internal (submersible) pumps. An external pump (or 2) will bypass the size limitations of the sump chamber.

Incidentally, I am not sure I will trust that amount of flow to a HOB overflow (I assume that is what you meant by "wier"). I would have a drilled tank & internal plumbing arranged so there is no risk of flood.

 

[Sco453]

jsoong

Thanx for the reply.

It will be drilled in several places, I've attached a PDFwith a rough mock up of how it will look. I'm going for a weir in one corner with a Durso system to keep the noise down.

As I'm scaling up from usually 3 & 4 foot system to as you say a monster tank, I looked at the figures (flow) involved and thought that trying to rotate somewhere near 20,000 litres an hour would be a nightmare and turn it into a whirlpool??? Mhy sump water height will be around 350mm (1 foot) so I'm not playing with a lot of area for pumps. Luckily though I am at design stage so can move and adjust things accordingly before committing to build.

Have a look and see what you think???

Sco

 

[jsoong]

You have a pretty well thought out plan. Few comments:

1. Your weir is basically an internal overflow box with rakers +/- baffles. I am sure you know there are calculators on how big that must be (based on flow rate). I would go at least 1.5 to 2x the minimum .... those rakers will get blocked & you want a good margin of errors.

2. I would have more than 1 drain line from the OF to sump. For your flow rate, you are looking at maybe a 4" drain ... that would look ugly .... Far better looking to have 2 or 3 smaller drains... plus you have redundancy.

3. I find it almost impossible to tune a Durso. I gave up after ~ 1 year & went with a partial siphon system. That was originally proposed in Reef Central, but is much better written up here:
BeanAnimal's Bar and Grill - Silent and Fail-Safe Overflow System

4. I like the idea of an emergency overflow. <The link above has one as well.> However, I would run the tank's emergency overflow to the sump. Should your active drains fails, the emergency will maintain tank circulation if it is routed to the sump, and also prevents burnout of your return pump. <Better pump has a temp cut-off ... I would suggest getting that esp. in external pump configuration. Even then, not having the pump on dry will lengthen its life.> BTW, my emergency line runs to the wet-dry compartment, keeping the media wet to preserve the bio-filter when my main fails.

5. I would keep the emergency overflow from sump to sewer as your ultimate failsafe against flooding.

6. As far as return flow is concerned, you will not have a strong current if you break up the return. You can divide the flow into 2 or more long spraybars, breaking up the flow into many smaller currents. This will decrease the water velocity while maintaining turnover, and gives better water circulation to boot.

 

[Sco453]

Jsong

Thanks for the advice. Splitting the syphons into 4 or more is a good idea, like you say it gives good contingency. I've been looking at the emergency drain system too, basically now I'm going with one on the display tank and the sump, hopefully they should never see water but I think if i'm going to the hassle of plumbing from the kitchen under the floor to my setup that an extra few fittings and couple of metres of pipe isn't going to break the bank

Regarding the durso, I'm a bit confused as to why people simply drill a hole to regulate air flow??? I'm going to cap off the tee piece with a valve which will give me total control from 0-100%. It seems that tuning is the key to success?? Likewise, knowing a bit about hydraulics, the pipe going into the sump will greatly affect overall performance too.

I was looking at some monster tanks using pool pumps and I suppose it is all relative to size, all systems need similar levels of turnover bit the pipe work steps up too which allows the 'current' to remain similar.

Good feedback mate, appreciate your time and thoughts.

Sco

 

[jsoong]

Drilling a hole to regulate the durso is cheap, & avoid having to glue a valve to the top of the cap. The problem I had was keeping it tuned.

My goal was for a totally silent setup. After hours of getting the Durso perfect (trial holes, plugging with silicone, repeat ....), it goes out of tune within days or hours. It seems the tuned Durso is only effective over a narrow range of flow rate. So as the pump output varies, (say from evaporation, a bit of stuff restricting flow in the pre-filter ... etc), the Durso goes out of tune. It was certainly still better than nothing when it is a bit out, but no longer totally silent. I tried having a variable air feed with a valve, but it is just too much work to keep adjusting the thing.

With my current system, it is silent over a wide flow range, and so is easy to setup & requires little adjustments. Only time when there is noise is when my pump compartment is almost totally dry from evaporation ... so it is actually a good thing. Instead of adjusting the valve, I simply top up the sump.