low pH level in tank

[trace1]

i'm having a similar kind of problem but i have 2 tank running did water changes on them both last nite & the smaller of the 2 tanks has a ph of 6.0 & on bigger tank its 6.8, the smaller tank just has 8 guppies in it & is a 55 uk litre tank & the larger tank has 4 female black mollies 6 neon tetras & 3 albino corys.
has anyone got any ideas ??
have heard that the guppies don't like low ph in water is this true
thanks

 

[@ombomb]

Guppies prefer water with a pH or 7.5+ really.

Either change your stocking to new world Chichlids / Tetra or think about changing your substrate to crushed coral / adding extra aeration to your tank to drive out the C02 (this is not the vest solution for live plants though).

 

[tttnjfttt]

sorry to have disagreed with your post. I was lashing out from personal experience

I was told a couple years ago (when I was trying to fix the ph in my puffer tank) to add baking soda. As I tested with it I realized that a teanie tiny bit goes a very long ways. I dont think it affects the kh and if it does not by very much, for I would raise my ph and it would be back down the next day. You might need more then I suggested since I was also adding aquarium salt I just wanted to make sure they did not over do it and shock the fish making things even worse.

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KH measures the carbonate hardness. Baking soda is know technically sodium bicarbonate, or NaHCO3. In water, the Na will break off, leaving HCO3.

Initially, in very acidic water, it may react and leave as CO2, but after tha, it will definately increase the KH

 

[rdd1952]

Guppies prefer water with a pH or 7.5+ really.

Either change your stocking to new world Chichlids / Tetra or think about changing your substrate to crushed coral / adding extra aeration to your tank to drive out the C02 (this is not the vest solution for live plants though).

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Everything I have read on guppies (and I don't have any) lists a very wide pH range for them - from 5.5 to 8.0. Here is the site I use most often for fish profiles.

 

[@ombomb]

I tend to look at Fishbasehttp://www.fishbase.org/Summary/SpeciesSummary.php?id=3228 which has them as 7 - 8.

 

[rdd1952]

I guess it really depends on where you look. I think guppies are pretty much like most fish. They will adjust to a pH that is not their optimal pH as long as it is stable.

 

[fawnmodel]

Baking soda (sodium bicarbonate) DOES increase the PH - in fact it is used for ponds, and more obviously - for increasing and maintaning PH in ALL public and private pools and spas.

1 tsp per 20 gals can raise the ph approx .5-1.0 Never raise more than one point in two days, and anything under 6.8 is WAY more toxic to fish than even up to 9! Because acidic water will EAT at the fish. Alkaline water can make ammonia up to ten times more toxic tho, so good water quality is paramount.

Obviously you need a test kit, testing before, and after (24 hours after) each change. Once it is at a correct level, you can add your ideal amount during each water change, testing before and of course, 24 hours after. .5-1 change at a time will not harm your fish, it is a slow aclimation. Fast changes is what hurts fish, in both temp and ph so long as you are moving in the right direction.

 

[Angel Lady]

Everything I have read about baking soda is it will increase the KH AND raise the pH. Killing two birds with one stone.

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This is so true and it is the safest way without chemicals..

 

[ejhh]

Time to revist this original problem.
pH is still low - fluctuating around 5.5 - 6.5 and I just don't understand why it keeps dropping.

I'll try and be as comprehensive as possible in summarising the situation.

1) pH of the tap water is 7

2) I'm doing 25% water changes twice a week and changes filters when necessary. Required filters are rinsed in old tank water.

3) I'm testing the water once a week using the "Interpet" master test kit. Results of tests are always around....
Ammonia 0, Nitrite 0, Nitrate around 12.5, pH around 5.5-6.5

4)The Interpet test kit does not include a KH test but I believe it's around 0 (found from one of those inaccurate dip sticks). The water around here in south west england is fairly soft (no scale in the kettle).

5) The tank now contains the following
- 2 gourmais
- 2 neon tetras
- one molly
- 2 silver sharks
- 1 LOF (little orange fish)
- 70 litres of water (around 24 degrees C - 75 degrees F)
- 2" of gravel
I've taken out the plants since they make it more difficult to use the gravel cleaner

6) The tank is a jewel 70 with integral filter system. I've added a little gizmo that introduces air bubbles on the filter outlet. (This has solved the lack of oxygen problem I've had before)

7) After a water change the pH goes up. After a few days it goes back down again.

8) Adding baking soda does increase the pH slightly but I don't consider this a long term solution.


WHAT I REALLY WANT TO KNOW is "why does my pH stay so low?"
My LFS can't explain it.

The fish seem to be happy in this water but (a) need to fix the problem before adding a few more fish and (B) this low pH is problem is frustrating me - why, why, why?


thanks in antici.....pation for you help.

Frustrated of Devon

 

[@ombomb]

Very odd, but if your KH is 0ish, then it's VERY hard to keep the pH stable. You can order KH test kits online and they are definitely worth having if you are having pH problems.

Do you have any bogwood in the tank?

My suggestion would be to consider baking soda a long term option and change the substrate to crushed coral. The baking soda should buffer the KH and substrate increase the pH, however I am not 100% sure to what degree the substrate would change the pH as I have never done this myself, so expirments in advance and extreme caution is recommended!

Another option would be to use RO water and the relevent addatives.

 

[sinistral]

A few points:

1. Baking soda will buffer your aquarium's pH to about 7.8. If you add it in sufficient quantities, you will raise KH (you can calculate the result here if you wish) and "set" the aquarium pH at about 7.8. If the pH of your water is lower, it will rise. If it's higher, it will fall.

2. I think the larger point is still to identify why your pH is low.

3. I think your aquarium has probably been overstocked for the past 6 months. Overstocking doesn't always show up in ammonia/nitrite/nitrate testing. Over time, the metabolic processes in a tank will produce various acids which will deplete the buffering capacity of your water and lower the pH. If you've been overfeeding (I don't know that you have been), this process will occur faster.

Mollies are messy fish for their size because of their girth. Silver sharks are also too large for a 15 gallon tank. What kind of gouramis do you have? Unless they are dwarf or honey, they're probably too big for the tank too.

You may wish to think about restocking the tank. There are also other causes of low pH that you may wish to investigate. You can read about them here. Hope that's helpful~