Two Tanks One Sump (freshwater) Ph Difference

Asomeone

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As the title says I'm considering combining the sump filtration I have for my 2 cichlid tanks.
One tank is a 50 gallon moderately planted tank that i regularly dose with flourish. The PH is between 7.2-7.4 This tank houses 6 firemouth cichlids and I filter this with a 20 gallon sump.

The second tank is an assorted 45 gallon african cichlid tank. The ph is 7.6-7.8. I have a canister and a HOB filter on this tank.
Both tanks are fully cycled, have very little nitrates and nitrites. 0ppm ammonia. I would continue running the canister and HOB for the Africans. I'd just add an overflow and return that pumps into this tank. It would enable me to use my current top off system for both tanks instead of purchasing and setting up a second one.

Since the tanks would now be connected, would the averaged PH have a significant effect on my plants or fish?
I'm figuring since the total tank volume would be 95 gallons, serviced by a 20 gallon sump, 350gph canister, and a 200gph HOB It would be more than enough support for the 2 tanks.
 

nikm128

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The averaged PH would be ok, around 7.4-7.6 I would imagine @toosie ?
What will the turnover of the sump be? For 95g you want around 760gph so with just the canister and HOB you'd be 210 short with 550gph so the sump turnover is very important to factor
 
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Asomeone

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The averaged PH would be ok, around 7.4-7.6 I would imagine @toosie ?
What will the turnover of the sump be? For 95g you want around 760gph so with just the canister and HOB you'd be 210 short with 550gph so the sump turnover is very important to factor
My sump currently has a 500gph pump that feeds the firemouth tank. I'd add a lower flow return pump into the african cichlid tank from the sump, maybe 200gph. So total id have 1250gph. Thats not really accurate since the flow to the sump wouldnt be the same for both tanks (but roughly).

I also just retested to make sure my numbers were accurate and the Firemouth tank is currently at 7.6 and the African tank is at 8.0. I'll be removing a couple big rocks from the firemouth tank that continue to raise my PH.
So the difference is greater than previously stated. After removal of the big rocks I assume it would differ greater. But, I'll probably run the tanks together before the difference is too large.
 

nikm128

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Ok you're definitely set with filtration then, in a perfect world your PH should balance ~7.8 which would still be ok for both cichlids
 
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Asomeone

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Ok you're definitely set with filtration then, in a perfect world your PH should balance ~7.8 which would still be ok for both cichlids
I'll go buy the PVC then haha, thank you!
 

toosie

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The averaged PH would be ok, around 7.4-7.6 I would imagine @toosie ?
The pH in the planted tank will vary throughout a 24hr period, with the highest pH usually being tested about an hour before lights out, because that is usually about the point in time that the plants have used as much of the CO2 available to them, before they start reversing their process and start contributing to the CO2 concentration in the tank.

Without knowing the GH/KH of each tank, and the tap water, it is hard to determine how different each tank is from the source water and the effects of the buffering systems in each tank. But I would be willing to hazard a guess that the pH of the combined system will settle out closer to the current pH of African tank.

African cichlids tend to prefer harder water, and plants tend to do better if water isn't too hard. So, the plants may not do as well in the combined system, but if you go through with this plan, I would be more concerned about fish needs than plant needs, so I wouldn't recommend trying to keep the Africans in softer water than they are currently accustomed to.

I think before you combine these waters, you should test the GH/KH and compare it to your source water so that you know better what you are really dealing with.
 
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Asomeone

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Thank you! I'll pick up a gh/kh test kit. Never tested for that before, only have that test on the crappy little strips.
 
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Asomeone

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Okay, got the tests and got it all situated. Results are as follow
Firemouth tank- 200GH 100KH
African Cichlid tank- 200GH 90 KH
Source 150GH 90KH
considering the comparable values of the tanks as is I'll be combining them. I am going to be researching these values further but any big numbers tend to worry me. The value sheet included in the API kit said that these values are extremely high and only suitable for rift lake cichlids. My fish all seem happy, My plants grow rapidly. Is this a problem?
 

toosie

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My fish all seem happy, My plants grow rapidly. Is this a problem?
That hardness level is suitable for both of your types of cichlids. So there are no issues there. If the types of plants you have are also thriving, then there are also no problems there either. If the pH for the plants goes up when the system is blended, then that might affect them some, but time will tell.

Rift lakes are about 200ppm to 400ppm which is considered very hard. But lots of water sources are at 200ppm, so a lot of fish thrive at that level. So while your water is hard, it isn't THAT hard.
 
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