Need Advice: Low pH

[Gabbie]

Tank:

• What is the water volume of the tank?
  • 40g
• How long has the tank been running?
  • 1.5 years
• Does it have a filter?
  • Yes -- Penn-Plax Cascade 1000 and Tetra Whisper 30-60
• Does it have a heater?
  • Yes
• What is the water temperature?
  • 80F
• What is the entire stocking of this tank? (Please list all fish and inverts.)
  • 1 adult and 2 juvenile angelfish
  • 10 rummy nose tetras
  • 5 kuhlI loaches
  • **Note, I bought this tank as a 55 gallon and at the time didn't think to measure and confirm. I am in the process of searching for a good deal on a 100-125g.

Maintenance:

• How often/much do you change the water?
  • Originally, 20-30% on a weekly basis. Once I noticed the pH problem, I moved to 20-30% twice a week.
• What do you use to treat your water?
  • 10 mL API Stress Coat +
  • 1 cap Seachem Flourish Excel
  • 1 cap Seachem Flourish
  • **Note, this is a relatively heavily planted tank and I do not have a CO2 system, therefore the addition of bioavailable carbon for my plants.
• Do you vacuum the substrate or just the water?
  • Rarely. My tank has MTS and I remove any dead plant material at each water change. I will hold my siphon an inch or two above the sand to suck up any top debris.

Parameters:

• Did you cycle your tank before adding fish?
  • Yes
• What do you use to test the water?
  • Tetra Easy Strips and API Freshwater Master Kit -- I use both as the test strips indicate chlorine, alkalinity, and water hardness -- I primarily use them for chlorine.
• What are your parameters?
  • Ammonia: 0 ppm
  • Nitrite: 0 ppm
  • Nitrate: 10 ppm
  • pH: 6-6.4 (after water change, 7.2-7.4)

Feeding:

• How often do you feed your fish?
  • 1/day, fast on Sundays
• How much do you feed your fish?
  • 2-3 pinches (I know, unhelpful 'unit' of measure) of pelleted food OR 1 cube bloodworms and 1 pinch pellet (1-2 times each week)
• What brand of food do you feed your fish?
  • Omega One Color MinI Pellets and Omega One Frozen Blood Worms

I will be totally honest, I have not checked my pH super regularly in a couple months -- only here and there since the aquarium had fish in it for several months. I know this is bad, after this, I will not skip checking pH again (so no need to scold me). When I checked the pH 2 weeks ago, it was between 6-6.4 in two of my three tanks (the information above is for one of my tanks, however, everything is virtually the same except for stocked fish and the amount I feed). Since I noticed the low pH, I have been doing twice weekly water changes on each tank and monitoring pH daily. My tap water has no ammonia/nitrates/nitrites and has a good ph (7.2-7.4). Fish are all doing well and are show no signs of distress/discomfort. In my 40g, I have a piece of Malaysian driftwood, however, I have no driftwood in my 17g where I have the same problems. Substrate in my 40 gallon is sand and CaribSea something gravel in the 17g. I have added some crushed coral to my the hob filter on my 40 gallon and plan to get more.

Finally, my question, what the heck is going on and how do I fix it? I would prefer to stay away from chemical solutions and solve the root of this problem, however, I have Seachem neutral regulator if it comes to that.

Here is a picture of the tank a couple months ago. It looks more or less the same save for there being 3 angelfish and not 4 and the plants have been trimmed.

 

[mattgirl]

Adding Crushed Coral to your filter or a piece of limestone to your tank should help stabilize your PH at the same level as your source water. Keep in mind it won't raise it instantly like some of the products designed for raising or lowering the PH so add it and give it a few days to stabilize. If it continues to drop add more.

Start out with about a cup of the CC in a media bag. If after 3 or 4 days the PH is still dropping add more. If you don't have room in your filter for the CC hang a bag of it situated where water will be running through it.

 

[Gabbie]

Thanks so much for responding mattgirl. I have added about 3/4 cup CC to my HOB filter -- that is just what I had in the house so I will make sure to grab more tomorrow. Any idea what could be causing this pH problem in the first place?

Again, appreciate the response!

 

[mattgirl]

Thanks so much for responding mattgirl. I have added about 3/4 cup CC to my HOB filter -- that is just what I had in the house so I will make sure to grab more tomorrow. Any idea what could be causing this pH problem in the first place?

Again, appreciate the response!

You are very welcome.

Have you checked the KH of your source water? If it is fairly low that may be why your PH drops. I have very soft water with almost negligible GH and KH. I have to run CC in my tanks to keep my PH stable.

 

[Gabbie]

You are very welcome.

Have you checked the KH of your source water? If it is fairly low that may be why your PH drops. I have very soft water with almost negligible GH and KH. I have to run CC in my tanks to keep my PH stable.

I've never actually checked KH, I will grab a test kit for it when I am out grabbing more CC! Hope this is the problem and that it's an easy fix!

 

[mattgirl]

I've never actually checked KH, I will grab a test kit for it when I am out grabbing more CC! Hope this is the problem and that it's an easy fix!

Hopefully adding the CC will take care of it for you. I know it works for me

 

[Inner10]

First off what's your substrate?