Day Night Ph Fluctuations

[tommyd193]

Hi gang! First time post, a couple of different questions, hope you can help.

My tank has been running about 18 months now; I had some challenges with phosphate and naturally developed a heavy hair algae problem but with the help your site and lot's of reading, oh and did I say LOT's of reading, I'm back in control of my nutrients it's been good for the last 4 months!

I'm now using Kalkwasser to administer calcium and maintain a good balance PH and dkH. It appears to be working, but I'm uncertain if I've got it quite right yet. It seems I have a “reverse” PH fluctuation; meaning, early am before lighting is on PH is a steady 8.13, albeit a bit low, but steady, by high noon, according to my lighting scheme the PH drops and shows erratic readings according to my digital pint point ph meter from 7.68 to 7.1. I know that some fluctuation is normal, but I'm concerned this may be a bit out of the normal range. Do you have any ideas what may be happening here? My meter is also new and I question if it's working properly. Although it’s well calibrated using the solution, the meter reacts differently in my tank with moving water. By sun down I begin the drip again and PH is back to a steady 8.13 in early am and the cycle repeats.

I really want to get my PH in the 8.3 - 8.4 range any suggestions? The levels appear to be balanced, test kits are good, and occasionally double checked with different kits just to be sure reagents are still good. If I add more Kalk I’m concerned about precip, also I’ve not tested for Co2 / dissolved oxygen??? I have more reading to do there to understand what it is and its impact to the tank.

Also what’s your opinion on doing water changes? I’ve read an article that makes a good case and demonstrates how water changes can actually deplete a tanks balance and reduce its’ additives simply because most salt mixes do not match the levels of a well established tank. If true and if top off water can be matched to the aquarium and nitrates are not an issue, with strict monitoring of all levels, can’t water changes be reduced significantly?


Tank Specs:

150 Gallon w/ built in twin overflow
220 lbs mixed fiji and tonga live rock
1 to 1 1/2 inches of Carrib sea aragonite
20 gallon wet dry/sump (bio balls)
using Chemi-pure, poly filter pad, Aqua C 150 Protein skimmer
Flow rate is 690 gph / Turn over 4.6 X per hr
Using Tropic Marin “Pro Reef” Salt Mix
15-25 % water changes monthly

Lighting: 576 watts PC's via Coralife 6x96 lunar Aqua light; timed 3hr sun up, 9 hrs full 3 hr, sundown

Salinity: 1.023
Temp: 78
Amm: 0
Nirate: 0
Nitrite: 2.5
PHos: .1
Mag: 1200
calcium: 380-400 (last consumption calc was 5)
dKh: 9
PH: 8.13 pre-sun up

Kalk dosing via Drip (seeking slurry):

[The Reefer91]

if your worried about day-night pH fluctuations, i believe i have a solution i heard somewhere.

if you have a refugium, you have the light on in reverse period. since it's when the lights are out that Carbon dioxide is released, you simply need a way to control it at night. since corals and algae(by corals i mean the algae on them) take it up when the lights are on, you need the lightn on at night. have the refugium dark ubntil the tank goes out, then have a timer that turns the fuge on. for this to work, you need a substantial amount of algae, and it would help to have some hardy coral.

hope this works

[tommyd193]

Yes I too am aware of the refugium but was hoping to not go down that path. But let me make sure I understand.... so Carbon dioxide lowers dkh and in turn lowers ph and this happens when the lights are out.. if understand correctly, then my ph should Drop in the p.m, right? However, mine drops with the lights when on causing a reverse affect.

I do have some hardy's basically the mix contains zoe's, cabbage leathers, open brain, elegence, finger leather, hammer, yellow fiji, toadstools, flowering tree and yellow sea fan. Most are doing well, some do react and open or close with the ph changes.

[DamageInc]

Drip 24hrs. That's what I started to do and my PH is dead 8.41-8.45 day and night. By the way, I'm slowly bringing it down to 8.2-8.3 area.