Pump Question

Zman

Hey guys i just have a question how BYAP pumps feed the GBs.

Do they go from the pump straight to 25mm pipe?

I am thinking of building 2 seperate systems with 1000l FT and 5x 360l GBs. I was thinking of having 50mm pressure pipe as the feed line on the ground then have 5 reducer Ts (from 50mm to 25mm) then to Gbs. The pump will be in the FT and will be constant flood.

Do i even need the 50mm feed pipe or should 25mm all the way from pump to GB be fine?

Cheers

RupertofOZ

Depends a bit on the number of grow beds,, and distance to pump...

But I usually plumb to the the largest size of the outlet of the pump... and then "tee" down as you suggest...

bythebrook

I've plumbed my three GBs with 40mm pipe, and stepped down to 25mm before the valves - because the 40mm valves are more expensive and much stiffer to operate. The larger pipe will have less friction than a smaller pipe, and there will be less pressure loss. Not a problem if you are pumping only a short distance (both horizontally and vertically).

I've also plumbed the system to allow for future expansion. ATM this pipe has a valve (40mm) returning excess water directly back to the FT, creating a swirl. I put the pump in the centre of the tank, so that it will pick up the solids deposited by the swirl effect.

All good things to think about before designing the piping.

Marc d W

+1 bythebrook
My last 2 growbeds I stepped the 40mm down to 25mm at the growbeds and found that the increased friction was enough to prevent the beds from filling in the 15mins. Clearly the pump was reaching its limit. So as Rupert says "it depends..." If you pump has heaps of capacity then it wont matter so much as it will if it is reaching its limit.

Cheers
Marc

bythebrook

Marc d W wrote:

+1 bythebrook
My last 2 growbeds I stepped the 40mm down to 25mm at the growbeds and found that the increased friction was enough to prevent the beds from filling in the 15mins. Clearly the pump was reaching its limit. So as Rupert says "it depends..." If you pump has heaps of capacity then it wont matter so much as it will if it is reaching its limit.

Cheers
Marc

Wow - 15 minutes to fill a GB! Mine fill in 3 minutes (and that includes closing the valve slightly in one GB so that they all fill evenly). This is including returning some of the pump flow directly back to the FT. I thought the idea was to turn over the FT volume in one hour, or 15 minutes if you are running 15 on/45 off?

Valves do have a significant pressure loss, so if you are at your pumping limit, try to make the pipe as large and as straight as possible, and don't have valves.

Marc d W

bythebrook wrote:

Marc d W wrote:
+1 bythebrook
My last 2 growbeds I stepped the 40mm down to 25mm at the growbeds and found that the increased friction was enough to prevent the beds from filling in the 15mins. Clearly the pump was reaching its limit. So as Rupert says "it depends..." If you pump has heaps of capacity then it wont matter so much as it will if it is reaching its limit.

Cheers
Marc

Wow - 15 minutes to fill a GB! Mine fill in 3 minutes (and that includes closing the valve slightly in one GB so that they all fill evenly). This is including returning some of the pump flow directly back to the FT. I thought the idea was to turn over the FT volume in one hour, or 15 minutes if you are running 15 on/45 off?

Well my pump (8000l/hr) has to fill 5 beds with extended standpipes and an extra hole in the bottom of the standpipe. My system runs 15mins on and 15mins off with some constant flood after feeding (I have trout and SP in the same system but separate tanks) . I have 5000l of water in my system so no hope of circulating all that in an hour and don't see the need to. It's a bit of a balance between a big buffer with the water volume vs getting rid of the ammonia. It works well for me.
The 12000l/hr pump is still in its box and will fill the beds faster but then I will probably have 2 more beds for it to contend with.

bythebrook

I'm running a 8000Lph pump (probably the same one as your's) on three GBs. FT is 3000L. By my calculations I would fill five GBs in five minutes (instead of the current 3 minutes), compared to your system taking 15 minutes. I assume we are talking about BYAP GBs?

I am also returning some of the pumped water directly back to the FT. If I ran all the pump water to five GBs, I could easily fill them in 3 minutes.

I don't think it is necessary to turn over a 5000L FT in one hour, but I'm glad you are running 15/15 if it taking the full 15 minutes to fill your GBs. What is restricting your pump - vertical height, small diameter pipes, long horizontal distance?

Marc d W

bythebrook wrote:

I'm running a 8000Lph pump (probably the same one as your's) on three GBs. FT is 3000L. By my calculations I would fill five GBs in five minutes (instead of the current 3 minutes), compared to your system taking 15 minutes. I assume we are talking about BYAP GBs?

I work it out as follows
8000l/hr pump
1m of head (friction in pipe and taps and height of the top of the beds above the water - note water drops in tank increasing head to more than 1m)
flow rate at 1m head = 6400l/hr
water pumped per 15 mins = 1600l
Approximately 3000l of media - assume 40% water in bed = 1200l plus water lost through the standpipe holes (3) over the 15 min fill time.
15 mins to fill the 5 beds is not unexpected especially when the sump tank is full (so my main tank is just over half full) and the pump is pumping water to just over 1m in height (top of water to top of bed) plus friction loss.

My beds also fairly well empty in the 15 min off cycle.
Cheers
Marc

bythebrook

Marc d W wrote:

bythebrook wrote:

I'm running a 8000Lph pump (probably the same one as your's) on three GBs. FT is 3000L. By my calculations I would fill five GBs in five minutes (instead of the current 3 minutes), compared to your system taking 15 minutes. I assume we are talking about BYAP GBs?

I work it out as follows
8000l/hr pump
1m of head (friction in pipe and taps and height of the top of the beds above the water - note water drops in tank increasing head to more than 1m)
flow rate at 1m head = 6400l/hr
water pumped per 15 mins = 1600l
Approximately 3000l of media - assume 40% water in bed = 1200l plus water lost through the standpipe holes (3) over the 15 min fill time.
15 mins to fill the 5 beds is not unexpected especially when the sump tank is full (so my main tank is just over half full) and the pump is pumping water to just over 1m in height (top of water to top of bed) plus friction loss.

My beds also fairly well empty in the 15 min off cycle.
Cheers
Marc

Thanks for that Marc.

The differences between the two systems (mine and yours):
I have only half a metre of head (maximum), running 40mm pipe backbone, and minimised the distance from FT to beds (and so almost no pressure drop) and the FT is nearly full (GBs return directly to the FT, I don't have a sump). I have so much flow that I divert some of the water directly back to the FT. I probably couldn't do this if I was filling two more beds, but they are planned in a system expansion, which is why I configured my system and bought a larger pump.

It shows the importance of correctly designing a system to minimise pressure drop and accurately sizing the pump for the specific system.

RupertofOZ

Here's a 6 bed system... 3000L fish tank, 1000L sump, six BYAP grow beds....

viewtopic.php?f=4&t=5725&hilit=shoalhaven&start=210

8000L/H pump to grow beds.... via 40mm pipe.. tee'd to 25mm into beds..... total length fish tank to furtherest bed... 25metres...

10000L/H sump pump... back to fish tank via 40mm....total length sump tank back to fish tank.... about 15 metres...

Timer cycle usually 15/45...

Charlie

Forgot about that one Rupe, got any updates?

RupertofOZ

Been doing a complete tidy up and replant Charlie...

Probably down on the weekend... I'll grab some photos then..

Charlie

Cool, thanks :thumbleft:

Its a spectacular set up.

Marc d W

bythebrook wrote:

The differences between the two systems (mine and yours):
I have only half a metre of head (maximum), running 40mm pipe backbone, and minimised the distance from FT to beds (and so almost no pressure drop) and the FT is nearly full (GBs return directly to the FT, I don't have a sump). I have so much flow that I divert some of the water directly back to the FT. I probably couldn't do this if I was filling two more beds, but they are planned in a system expansion, which is why I configured my system and bought a larger pump.

It shows the importance of correctly designing a system to minimise pressure drop and accurately sizing the pump for the specific system.

I agree Bythebrook. With these pumps they are so unforgiving with any increase in head and designing your pipework with this in mind is so important if you want to use the smallest pump possible.
The drop in the main tank was the killer for me.
I forgot to mention that I used 40mm pipe all the way up to and including the taps.
On the positive side, when i expand I have the bigger pump (uses less power so an added bonus) and the 8000l pump is the backup.

Charlie

What 8000 pump did you buy Marc if you dont mind me asking

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Pump Question

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