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Ph vs total alkalinity

9K views 21 replies 7 participants last post by  jgilvey 
#1 ·
Hello all.
Quick question.
I have a 60 gallon with some frontosa and calvus in it. My water out of the tap comes out at about 7ph. After some research I started buffering my water with baking soda and Epsom salt in hopes of getting it somewhere around 9 for the calvus . After some tinkering with the formula a bit I got it to about 9 or maybe just a bit lower. The problem is that the total alkalinity is off the charts high. It's over 300ppm. My test strips don't even have the color on the chart that I'm getting on the strip. The fish seem fine. My question is, is this safe for the fish and if not, hot do I correct it?
Thanks everyone
 
#2 ·
Phil,

Alkalinity is pH, so I am not quite sure what you are measuring in ppm. My first impression is that you are measuring total dissolved solids with respect to hardness. I lowered mine by reducing the amount (by 2/3rds) of epsom salts I added during water changes.

I don't know if this has any value for you, but I came across this article By Dr. Paul V. Loiselle from a Q&A:

http://www.fishchannel.com/freshwater-a ... hlids.aspx

Q. From books, fish magazine articles and word of mouth, I've learned that it is best to keep the pH of the water in an African cichlid fish aquarium between 8.0 and 8.2. Possibly because of my routine of frequent water changes, I've never been able to get a reading higher than 7.4 from my aquarium water despite the use of coral gravel for the substrate. Does this lower pH value pose any problem to my fish? If so, is there any other way of raising it other than through the use of a commercial buffer solution?

A. Your question would be easier to answer if you had specified exactly which African cichlid fish you are keeping. Because you have expressed concern over whether your pH is sufficiently high to keep your fish healthy, I assume you are keeping either Lake Malawi or Lake Tanganyika cichlid fish. Published pH values for Lake Malawi range from 7.7 to 8.6, and for Lake Tanganyika from 7.3 to 8.0 (I think it is supposed to be 9.0-Joe). Reported hardness values for Malawi range from 6 to 10 degrees of hardness (DH) (125.0 to 170.5 parts per million total dissolved solids - ppm TDS), and for Lake Tanganyika from 10 to 12 DH (170.5 to 205.0 ppm TDS). Experience has shown that both Tanganyikan and Malawian cichlid fish will prosper and breed at pH values as low as 7.2 and hardness values to 3 DH. What seems critical is the stability of these values rather than their absolute magnitude. Your use of coral gravel as a filter bed provides all the stability your fish require given the relatively hard, alkaline character of the tap water where you live (Southern California).

What is far more critical to successful husbandry of rift lake cichlid fish is proper nitrogen cycle management. These cichlid fish are extremely intolerant of ammonia and nitrite. The program of regular partial water changes you presently practice may depress the pH in your aquarium somewhat, but its contribution to the well being of your fish far exceeds any imaginable benefits from a higher pH. Your management practices are exactly those I would recommend to a prospective rift lake cichlid fish aquarist. Just keep up the good work and don't lose any sleep over those pH values.

Joe
 
#3 ·
Total alkalinity is not pH. It is the buffering capacity. Baking soda will raise pH to about 8.2 or so, maximum, no matter how much you add. If I remember correctly, the total alkalinity target in swimming pools is around 120 to 180, which keeps the pH stable at 7.6.
Regardless, it isn't necessary to keep rift lake fish at high pHs. They do quite well in low 7s.
 
#8 ·
DieselPhil said:
Thank you. I read that if I can keep PH at 9 and water temps at about 80 the calvus will grow faster.
You can drop your pH (slowly) to 8.2 ish and your altos & cyphos will be fine (no need to pay for the chems to raise up to 9.0 pH).

I've did the baking soda/epsom route and I much prefer using SeaChem's Tanganyika buffer. I buy it in bulk - much more effective than baking soda.

Russ
 
#10 ·
#12 ·
jgilvey said:
Wow - you could literally buffer Tanganyika with that huge bucket. :) Tough to find anything from Seachem on what it's made of - does it raise KH only? My GH is 16-17dGH, which is fine, but my KH is a little low at 5-6dKH
My pH out of the tap is 7.4. With several big tanks and fry tanks, I go through the paint can size every couple months. I like the bulk size as the price value is the best and I would use it.
 
#14 ·
I downloaded Seachem Tanganyika Buffer and all the ingredients are proprietary. So there is no information as to the types of carbonate salts used. Don't know why they would do that unless they didn't want you to know that they use sodium. So if it contains sodium salts it just like adding sodium bicarbonate. As far as I know there is no manufacturing method for calcium bicarbonate although you can have it present in solution. Most prefer not to add too much sodium to their tanks.

Using sodium bicarbonate the equilibrium pH of HCO3(1-) in water is 8.3. Adding more will not increase the pH but will increase the alkalinity. That's what DieselPhil experienced. Not knowing the ingredients of SeaChem's buffer I don't know what is in it to raise the pH higher. Above 8.3 you will start generating CO3(2-), but the dominate compound will still be HCO3(1-).

Thinking about this some more there has to be calcium carbonate in the SeaChem buffer. You can get the same effect by adding crushed seashells.
 
#17 ·
I kind of let the tank get away from me over the holidays as it was nuts at work for a few moths, so I did have algae issues. But not that I'd attribute to Potassium. Is that a known trigger? Typical E.I dosing will add lots of K as well from Potassium Nitrate/Mono Potassium Phosphate/Potassium Sulfate, but I've not heard it's an issue.
 
#18 ·
I don't know. Curious. I'll search and see if I come up with something. I use sodium bicarbonate and epsom salt along with cichlid salts and trace. The substrate is crushed shells. My pH is in the 8 range, can't tell exactly with colorimetric method. But typically sodium bicarbonate in solution has a pH of 8.3 so I'll go with that. The GH is around 24 and the alkalinity is off the scale. You said your pH with the potassium bicarbonate is 8.2. Is that checked with a meter?

I would rather not use sodium. Where do you get the potassium bicarbonate?

You add nitrate and phosphate. You are able to keep nitrates down with just water changes? The phosphates will add add to algae growth.
 
#19 ·
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