measurable effects of lower pH

[eliasi]

Ok folks.... bear with me because my dumb-**** brain is ticking over and it's probably going in a completely ridiculous direction.

So, everyone says not to be afraid of lower pH in a reef tank as long as it's stable.

To me, 7.8-7.9 seems really low, so it got me thinking, has anyone ever bothered to try running a calcium reactor driven by pH value rather than effluent value, at those pH levels of (7.7, 7.8, 7.9) and measured the effluent dKH. Correct me if I'm wrong, but if those pH levels are suppose to have no "ill-effect" on coral growth/health, then the effluent dKH measured should be identical to that of the tank water. If it's any higher than the tank dKH, would that not indicate that the material has begun to dissolve?

To my way of thinking, this is the only measurable way to determine if lower pH levels do or don't have any negative effects on coral skeleton growth.

Thoughts?

 

[GainesvilleReef]

You are conflating dissolving with precipitating. Corals grow by locally elevating the ph such that the calcium carbonate precipitates and forms the skeleton. Corals can still grow at a pH of 7.8. But, it is much easier to precipitate the calcium carbonate at 8.2. This has been tested and measured in labs many times. Also, the precipitation and dissolving of calcium carbonate are a function of pH, dKH and Temperature not just pH. Corals grow better at 8.2 than 7.8. But trying to force a tank to 8.2 that naturally wants to be at equilibrium 7.8 is complicated and can be detrimental to the tanks inhabitants. For this reason, most people say don't worry about it.

 

[MikeyG]

I am having a similar low ph problems.

For over 6 months my ph has ranged fro 7.8 to 7.98.

I have tried using kalkwasser to increase it, but that led to other problems so I have discontinued it.

I have my skimmer (Reef Octopus Ext 3000) air intake pulling air from the outside.

I am doing 6gal auto water change daily using Apex DOS.

Here are some specs of my system.

300gal display tank...400gal total body of water.

50 fish...mainly large show size tangs


Mixed reef with lots of hard and soft corals.

CA 440

MG 1400

Kh 8.65

Po4 0.06

No3 0 to 0.5

Temp 77.5 degrees.

Triton Core7 dosing...34ml daily

50 gal refugium with fast growing catho.

302 Aquatics algae scrubber sized for a 600gal system. Have to clean screens weekly due to rapid growth...

Lighting cycle for both refugium and scrubber is 20 hrs.

GFO reactor

Red Sea No3Po4...dosing 30ml daily.

Feed cycle is every other day using the DIY recipe from BRS.....my fishes are so greedy nothing falls to the bottom.

Lighting period is 14hrs. 3 hr ramp up 3 hr ramp down.

2 four feet Aquatic Life 54w T5 and 4 Kessil A360x

You will notice I am running a combination of nutrients reduction methods, because this is the only way I have been able to keep both nitrates and phosphates low.

Not sure how the heavy bio load from the 50+ fishes are contributing to the low ph.
PS...my tank is in the basement

Overall the livestock is doing well with the exception of some tissue recessive in some of the soft corals.

I don't want to become a mad scientist chasing numbers, but would love to have a better idea of what factoescare contributing to the low ph.

Thanks

Mike
Avid BRS customer.

 

[GainesvilleReef]

With the refugium and algae scrubber is the NOPOX redundant? It definitely contributes to low ph due to the vinegar in it. I do like some minimal carbon dosing but you could probably dose a lot less.

 

[Dlealrious]

I'm guessing due to keeping tanks alk at 8.6 u are running ur calrx at a lower ph to melt more media which is bringing ur tanks ph down