What happened to my pH?

[Elle2]

I am in day 13 of my cycle and everything seems to be going smoothly except my pH which has dropped below 6. I have been able to find information on why pH levels increase but not on why they decrease.

I am assuming that its not my tap water because my first test (4 days into cycle) showed a pH of 7. I have not done any water changes or added any materials since then so I have no idea why mine would drop so drastically or what to do about it.

Any thoughts or suggestions? (tank details below)

20 G
two Java ferns (one corkscrew grass that died and was in tank languishing for a few days)
pool filter sand
two pieces of driftwood

 

[Jchillin]

two pieces of driftwood

Driftwood can soften water but nowhere near an entire point. I agree it isn't your tap water. What are you using for an ammonia source and what type of test are you using?

 

[Lonewolfblue]

At this point, I would do a 50% PWC to bump the ph up some, then see where your ph and ammonia are. The decomposing shrimp should still be maintaining a constant supply of ammonia, so you won't stall the cycle by doing the PWC's. And since it's fishless, you could try adding just a little fresh baking soda to bump up the kh a little, which will also help the ph be a little more stable. As for how much, maybe someone can chime in. I just used PWC's myself in the fishless cycle to up my ph.

 

[newfound77951]

Do you know what your kH and gH are? If they're very low then your pH will be susceptible to sudden changes.

 

[Elle2]

The most recent data I can find indicates that the pH is quite low- 6.2-7 so I am now wondering if there was something in my tank that raised the levels during the first week. The kH seems to range from 3.8-4.6 but I couldn't find any data on the gH.

I will test the pH on some tap water- to do this do I have to let it sit for a while or do I test right away?

If my water is naturally low and I can't add baking soda once I have fish does anyone know what I can do to raise the pH?

 

[rich311k]

You can put some crushed coral in your filter it will raise your PH and keep it stable. You only have to replace it every 4 months or so. I would wait until your cycle finishes.

 

[Jchillin]

I will test the pH on some tap water- to do this do I have to let it sit for a while or do I test right away?

Let it sit out overnight prior to testing. You haven't mentioned what type of Ph test you are using.

 

[Elle2]

Its a freshwater master test kit.

 

[Lonewolfblue]

Once the cycle is complete, the ph will stabalize. Nothing to fear there. It's just during some cycles, the ph tends to crash. But that's quite normal for some people. A quick PWC will help keep the cycle from stalling. How's your ammonia and nitrite looking?

 

[maxwell1295]

If your tap water is very soft to begin with, adding driftwood can (and will) cause a pH crash. It happened to me. I use baking soda to up the KH (and pH) and add some with every PWC. I try to keep my KH up around 6-7 since I am now injecting CO2. Ph is around 7.0. Prior to do this, my pH was 6.6 and KH was 1dKH.

Edited: I meant KH and not GH

 

[DeFeKt]

I think one of the first questions here should have been, what exactly are you going to keep in there, and what water parametres are you aiming for?

Matt

 

[Elle2]

Once the cycle is complete, the ph will stabalize. Nothing to fear there. It's just during some cycles, the ph tends to crash. But that's quite normal for some people. A quick PWC will help keep the cycle from stalling. How's your ammonia and nitrite looking?

The nitrite and ammonia seem to be moving along smoothly... my ammonia was very high a few days ago (8 ppm) and I was going to do a PWC, but then it dropped to 1 the next day. I will do the PWC for the pH first thing tomorrow.

I use baking soda to up the GH (and pH) and add some with every PWC. I try to keep my GH up around 6-7 since I am now injecting CO2. Ph is around 7.0. Prior to do this, my pH was 6.6 and GH was 1dGH.

how much baking soda do you add?

I think one of the first questions here should have been, what exactly are you going to keep in there, and what water parametres are you aiming for?

I am hoping for some balloon mollies, a few platies or swordtails, some rummy nose tetras, a couple of cories and a kuhli loach.

 

[TomK2]

I would bet that your water is low in KH, and prone to pH drops when things are not stable. Yes, some Crushed coral in the filter can help raise KH and pH. Remember, nitrifying bacteria are significantly impaired by a pH of 6.5, and nitrification stops at a pH of 6.0, so you have reason to be concerned about your pH during the cycle. Water changes to keep the pH up, or crushed coral seem like a good idea. You could alwaysuse baking soda cautiously for a short term solution too.

 

[Elle2]

After doing a PWC and adding some baking soda my pH is still at 6. My ammonia finally hit 0 but my nitrites are still at 5 so I really don't want my cycle to stall. I won't be able to make it to a pet store that sells coral tomorrow- should I do another PWC? Are there any other quick fixes? I only added a very small amount of baking soda because I did not know how much to add.

Would adding a light coloured rock (the ones the LFS told me not to buy because they would raise my pH) be an option?

Thanks.

 

[Lonewolfblue]

A small piece of limestone or the rock you mention may temporarily help. Doing crushed coral in the filter is not instant, takes time to dissolve, as does the rock. The baking soda is the only thing that's instant, and should only be done a little at a time, even with no fish, as a major shift in ph could affect the bacteria. I put a handful of crushed coral in my XP3 over a week ago, and my kh hasn't moved yet. It's still at 60. I can get it to 70 after a PWC, but then after 3 or 4 days, it's back to 60. So I must be on the edge of the test kit between 60 and 70 (6 drops versus 7 drops from the liquid test kit).

 

[Elle2]

Thanks. I will pick up some coral asap. When you say "a little at a time" how little are you talking about? I literally only put a pinch in simply because I wanted to err on the side of caution. Since I have no fish can I add it right to the aquarium or do you recommend I add it to water and then add the water to the aquarium? My ammonia dropped from 8 to 0 since Friday so I am hoping this is a sign that my cycle has not stalled.

 

[Lonewolfblue]

What I mean by a little at a time, is you don't want a large ph spike to occur because of adding too much. I think it's safe to add directly to the tank, as there's no fish and it will dissolve quickly. Try a couple more small pinches and give it a little time to circulate and check your ph again. And kh if you have the test kit.

 

[Elle2]

Thanks so much! I will do this tonight and test again in the morning.

 

[Elle2]

I added baking soda last night and today it raised to 6.4 so I will add a little more today and keep testing. Do you know if this has an almost instant effect? Could I just keep adding and testing shortly afterwards until I reach 7... or is there a danger in it spiking hours later or the following day?

Thanks again for all the help.

 

[TomK2]

Once dissolved and allowed to circulate, it should be measurable. I see no reason why you couldn't test in 15 or 20 minutes if you think you need to repeat.