Basically, to prevent any pump overdriving another pump issue, you could/should plumb up as below.
1. Two independent circuits, quite commonly done to keep CO2 injection away from filters etc. Also easier straight through plumbing, easier to maintain, easier to implement, no T joints, no flow going wrong way issues, a total flow rate of 16,500 l
🙂)), a lot of positives for this method. This method both pumps can be kept underwater in the sump, so no issues of running dry if power fails. Each pump will need to be in its own sump section as if in the same section one pump might remove all the water and end up running the other pump dry.
2. CO2 injection loop in main pump circuit. Make the pipe after the 10,000l pump bigger than pump pipes, as it now has to take 10,000l + 6,500l flow as in diagram. This could be made from say a length of 40mm (or 32mm) solvent weld plastic waste pipe, with suitable T pieces and hose barbs. Again no issues of pumps fighting each others flow. Notice I the reverse flow of the 6,500l pump compared to your original diagram. Careful thought need to be taken with possible failure modes.
You will also need to consider all the possibly failure modes of such systems:
- If not careful during power failure you will end up syphoning the main tank into the sump and then onto the floor !!!
🙂eek
🙂.
- After power failure need to ensure that pumps can't run dry (like in first diagram if both pumps are in the sump) as most pumps won't self prime if full of air.
- If one pump jams/fails is powered off system won't overflow sump or main tank.
- Ease of maintenance and cleaning of the system.
