Noob with PH question ...

[ReefDog]

Hi all -

Started cycling my tank 10 days ago ... Last weekend I took my first readings:

Readings ... taken with API test kit

PH - 8.2
Ammonia - less than .5ppm (hard to match exact color)
Nitrites - 0
Nitrates - less than .5

I have not made any water changes, and have only added a very little bit of freshwater to cover evaporation - The only difference in the tank is, Yesterday I did remove the LR rubble I had in the filter as many people said that may result in excessive nitrate production.

So, today I took more readings ... All levels were exactly the same except the PH had dropped to 7.4. In reading some of the posts and articles on Cycling the tank I don't see anything to indicate changes in PH.

My plan is to let it continue cycling on its own w/out any intervention, but I am curious if the PH change is expected or a problem maybe ??

About my tank ... BioCube14 (10 gallon), standard 3 chamber filtration system w/106gph pump, 1 x 24 watt 10,000K 1 x 24 watt Actinic 2 LED night lights, 100 watt heater. No mods to the tank.

Any and all input welcome !!

Thanks for reading my post

 

[ReefDog]

I did some additional reading and may have found my answer ...

1) I should test Ca, Alk, and Mg as one of these (particularly ca) may be disturbing the PH level ... Sound like a good approach.

2) I have been using tap water to cover evaporation which has only been a tiny bit, but I just read the cumulative effect of straight tap water additions may cause PH levels to go haywire.

Since I need to use freshwater for evaporation would buying some distilled water from the grocery store be good enough ?

 

[Ritsuko N]

Distilled water is not the best water to use becuase it has absolutely nothing in it mineral wise like RO/DI water would, but its far better than using tap water. So I think for a little while you can get away with using Distilled water without much issue. That should give you time to get a jug and get some RO/DI water.

Ca, Alk will definitely have an effect on Ph readings in the tank. Using a good quality salt miz should aleviate those issues.

Now on anther note...when the lights are off such as at night the Ph levels will fall signifcantly. If you are testing your water minutes after the lights suddenly come on then you could indeed be getting a somewhat false low reading which is normal and to be expected. As the oxygen in the tank becomes lower at night when the lights are off then Ph will take a dive. This is why those that have refugiums will often run thier refugium lights on a oppisite photo period from the main display tank to prevent dramatic Ph changes. If you test the water later in the day after the lights have been on for a few hours you will often find that you have a higher Ph reading. If you are still having a low reading then using a buffering compound and checking Alk and Ca would be your next move.

HTH's a little...

 

[ReefDog]

Perfect ... I will 'upgrade' my fresh water source and try testing later in the day. If all else fails I will start looking into Ca and Alk levels.

Thanks for the tip !!