low pH problem

[Adobe1234]

I set up a freshwater tank about 9 weeks ago. The pH at setup was about 6.6 to 6.8, and was stable during cycling. However, in the past week I just noticed that the pH has dropped to 6.0.

Setup: 5 gallon, 1 betta, 2 nerite snails
Substrate: gravel and glass marbles
Filters: 1 HOB (Marina S10), and 1 sponge filter
No live plants
Parameters: 0 to 0.25 NH3/0 NO2/5 to 7 nitrates
I don't have a GH/KH test kit (currently on order); when I first set up the tank, however, I used some test strips that told me there was low alkalinity.
Tap water: 0.5NH3/0 NO2/0 nitrates/pH 7.6

Partial water changes do not seem to change the pH of the tank at all. I have resisted trying to fiddle with pH, as most seem to advise against this. However, I am concerned that the pH is so unstable and will not be compatible with life for my betta and snails. I am thinking of adding a small amount of crushed coral to the filter.

Any advice on
1) what type of monitoring equipment is best for adjusting pH?
2) how much crushed coral to add/ schedule for adding the coral and subsequent testing?

Thanks.

 

[Delapool]

I use a ph and kh test kit for tracking ph. At a guess, try a tablespoon of coral. You will need to dial it in and may get a quick ph increase and then it will slow down.

 

[tlonghorn]

Just get a pH balancer at your lfs there's a billion products

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[Adobe1234]

What are some examples of pH balancers? Do you mean something like Seachem Neutral Regulator? Or using Seachem Alkaline and Acid Buffers together?

 

[Caliban07]

What are some examples of pH balancers? Do you mean something like Seachem Neutral Regulator? Or using Seachem Alkaline and Acid Buffers together?

They only work temporarily and can cause unnecessary fluctuations so I am led to believe. Crushed coral in a bag in your filter will naturally raise ph and keep it there.


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[Adobe1234]

OK, I think I will start with a small amount of crushed coral.

One other thought--last week during a water change I used API StressCoat b/c of a tear in one of my betta's fins. Could StressCoat lower the pH?
I already tested tap water treated with Prime after sitting overnight (ph 7.6 right out of tap vs 7.4 after sitting overnight with Prime) I am thinking of rerunning the experiment with StressCoat instead.

 

[Delapool]

OK, I think I will start with a small amount of crushed coral.

One other thought--last week during a water change I used API StressCoat b/c of a tear in one of my betta's fins. Could StressCoat lower the pH?
I already tested tap water treated with Prime after sitting overnight (ph 7.6 right out of tap vs 7.4 after sitting overnight with Prime) I am thinking of rerunning the experiment with StressCoat instead.

I would of thought stress coat would be similar to other water conditioners if it did.

Ph between water straight from tap and left to stand will change naturally as it degasses noted just in case. Would be interested in what you get.

 

[Fresh2o]

I'm thinking something in the tank is bringing down the pH.
You could set aside three small glasses/cups of treated tap water, add some gravel from the tank to one glass, add some marbles to another (those these really should be inert), and leave the third alone (just water). Take a baseline of the pH. Let it sit for a day and retest. If there is a drop in the glass with the gravel, marbles, or both, then you have found the culprit.


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[Adobe1234]

Thanks for the good ideas -- will need to run some tests.

Another potential issue: I figured my tank was not completely cycled (because NH3 readings still at 0.25 most days with API kit)-- although at such a low pH it is probably mostly ammonium and not being consumed by the beneficial bacteria.

Anyhow, because I was hoping to buildup my biological filter some more, I haven't rinsed out any of my media. The downside: a build up of waste in the filter media could be another culprit for lower pH. Filtration includes: 1) sponge filter 2) HOB filled with matrix, Biomax, 2 sponges. Should I try rinsing some of the sponges in dirty tank water? How often do you do sponge maintenance?

 

[BillD]

Keeping solid material out of the filters goes a long way to maintaining their efficiency. As well, removing solid material before it breaks down, slows the rise of nitrates. When you say partial water change, how much are you changing? The betta won't mind that pH, although the snails might. Seems odd that the pH is dropping that much. Most tap water is purposely kept alkaline to reduce damage to delivery pipes and to allow the chlorine to do it's job.

 

[Adobe1234]

Here's an update.

Yesterday, I replicated the water I had prepared for my last water change (0.6 gallons) right before I noticed the pH drop to 6 about a week ago:
Tapwater only: baseline 7.8/after 12 hrs pH 7.6
Tapwater treated with Prime and StressCoat: Baseline ph 7.8/12 hrs later ph 7.6
Tapwater treated with Prime and StressCoat + gravel: baseline pH 7.6/12 hrs ph7.6
Tapwater trewated with Prime and StressCoat + marbles: baseline pH 7.6/12 hrs ph 7.6

Will test again after 24 hrs, but so far no big differences seem to be associated with StressCoat or substrate.

I went back to my records from when I first set up the tank (marbles/2 decorations/1 betta) and pH was 6.6 at baseline (day 1) -- I didn't test the tapwater at baseline for comparison. But don't know why my tapwater at least right now is so much higher.

As for the tank, I added about 1/2 tsp. crushed coral to the filter 2 days ago with no pH change detected.

Also, last night did some tank maintenance:
1) rinsed out the sponge filter in dirty tank water
2) added 1.0 mL Stability (I'm paranoid about losing my beneficial bacteria)
3) added a handful of gravel (gravel was getting low in spots; last time I added a layer of gravel to the whole tank pH increased by 0.2 but then went back down then next day). 4) 1 gallon water change with gravel vac in a small area (20%).

This morning ph was up to 6.5. Other water parameters are holding steady (0.25 NH3/0NO2/5 NO3). This morning I turkey basted the gunk from the bottom of the filter box. I plan to do some more HOB maintenance next.

Questions:
-How long should I wait between rinsing out each filter component?
-How often should I clean each filter component? (sponge filter, HOB with Biomax/Matrix/Sponges)