Substrate Question

[nc_nutcase]

I'm nearing the end of construction on a 6' x 6' @ 2.5 deep 550 Gal indoor fish pond in my basement. I'm considering different substrates for this tank...

My local water has a low PH of around 6.2 so I'm considering using a 50/50 mix of crushed coral and pool filter sand. I'm totally inexperienced with the use of substrate to offset PH. Will some blend of these two materials do what I'm looking for (7.0 - 7.5 PH)?

 

[littlefishie]

Any marine substrate will raise pH, but there's another FW substrate that buffers the pH. It's called Hagen Geosystem sand.

This is for your oscar pond, right? Wouldn't it be better to just acclimate them to your pH rather than mess with the pH using chemicals?

Though if you really want to, why not use a liquid buffer designed for cichlid tanks? You'd have to spend a fortune on it though..

 

[sylvia]

Oscars aren't hardwater fish though... so cichlid buffers designed for rift lake cichlids would be of no use. I'd acclimate them to the 6.2 pH. It shouldn't take long and oscars are highly adaptable. If they are from your area, they won't need to adapt anyway. I believe coral will raise your pH to 8.0 and I don't know whether the amount you use actualy changes this or not. Even if it was to the right pH, water changes would cause unecessary fluctuations that would be more damaging than the steady, but a little low, pH you have now.

 

[nc_nutcase]

I should have added previously, I also plan on adding a pretty heavy load of driftwood to the tank. I've been told this lowers the PH and since mine is already low (6.2) I thought I'd do something to counter balance it.

I'm siding with using coral to raise the PH as opposed to chemicals for several reasons, one is since I’m treating 550+ Gallons it would cost a fortune (I intend to do 50-100 Gal water changes weekly). Also I've just had bad luck with chemicals adjusting water condition. Seems to me that having the right filtration and natural decor is much more practical and simplistic. I was looking at coral substrate today and some brands claim that they never lose their effect on the environment which I much prefer over adding chemicals weekly.

So additional question, will adding 12-15 pieces of 14 - 24 Inch driftwood lower the PH enough on a 550 Gal tank to raise a concern?

I haven't been in this area long (Charlotte, NC) and the when I previously kept aquariums the PH was at a level much closer to what I wanted, so I never really bothered to learn much about adjusting it.

 

[yvez9]

how do you plan on doing water changes?

If you change 20% of the water at a time, then it could cause pH shock every time if there is a 2.0 difference between waht goes in and what's in there.

if you use some sort of drip system with an overflow, then the pH would buffer higher than 6.2 but be stable

if you let drip 1 gallon per hour in there, you will have a sufficient water change going on all the time

 

[andywg]

I know that with the cichids you want in there that plants are a no-no, however CO2 can help push CO2 down a bit. All you'd need for that would be about a 5 gallon tub to breed yeast in...

 

[nshockeyplaya]

Oscars can live in a PH anywhere between 6.0-7.5. Therefore dont even bother witht the ph as they will be perfectly fine in any ph bwteen there if adapted to it.

 

[nc_nutcase]

I highly appreciate everyone’s input here. I've received much food for thought. As of now I'm still playing with ideas and have not made a decision. I understand that the shock from fluctuating PH at water changes is unacceptable. I am willing to look into a drip water change system in the near future but have no experience with them what so ever so it will truly be starting from scratch.

What if I removed 50 Gal of water once a week on my heavy cleaning day (every Tuesday I spend 3-6 hours doing water changes and tank cleanings already) and then added 5 back each day. I know the maths doesn't add up but I would adjust so I remove enough to vacuum and clean properly and replace in 5 gal increments spread out as evenly as possible.

I don’t mind the water level somewhat fluctuates. It’s not like an all glass aquarium with a plastic rim where you can obviously tell when the tank is a ¼ inch low. When the pond is “full” it will be about 5 inch below the actual top rim of the pond. So if it varies between 4 and 7 inches below the top rim that is fine with me.

So do you think refilling 5 Gal at a time will remove the threat of PH shock (remember 5 Gal is less than 1% of the overall volume)?

Just ran some numbers. 1 inch of water in my pond is 19 Gallons. So removing 50 Gal when cleaning only lowers the water level 2.5 inches. Not enough to concern oneself with. The maximum volume of the pond is 660 Gal when filled to the rim (which I know would be unsafe for several reasons) and when filled to my “full” line (5 inch below top rim) is 564 Gallons