pH problem

toddpolish

toddpolish

Member
info:
90g tank, 7g refuge, 7g in sump. amm=0, trite=0, trate=2 (yes it has cycled)
tank is 2months old - no fish yet. just royal urchin, 12 turbos, 4 red hermit crabs.
I did water change this past weekend of about 10g. my pH was 8.0 - tried to up it by doing another water change. I did one tonight of ANOTHER 10g.
an hour later and the pH is 7.7
I'm using RODI. my turnover is at least 13x.
this is irritating. why is it going down instead of up.
 
toddpolish

toddpolish

Member
let me just add this... one of the salifert guys emailed me and said that some of pH reagants are not measuring correctly. They are sending me another test.
However, in waiting for this to arrive (over 2 months now) I bought another salifert pH test kit and the readings are the same.
is it the test kit or really a pH problem? any suggestions on what to do? (last resort being chemicals)
 
lesleybird

lesleybird

Active Member
Dear Todd,
I am new to this hobby, but my guess is that the city water that you are making RO seawater from has a lower PH to start with. I was told to use a good marine buffer when my PH was falling. The people at the aquarium store tested my water for carbonate hardness.....I think it has something to do with the water's capacity to maintain a PH of around 8.3 when there are things in the tank that keep making the PH go down ( I think it is the ability to pick up extra hydrogen ions). Anyway, you don't really have to understand it perfectly to use a good marine buffer to raise and maintain the PH. I just got one last week from **************.com called 8.3 Seachem Marine buffer...it says that it helps to maintain the proper PH even if you inadvertently over dose the product. I used it to raise the PH of some RO seawater that I purchased at the fish store yesterday. I bought some really easy test strips by Jungle at the above mentioned to test for PH and another to test for carbonate hardness. I found out in seconds with a dip of the test strips that my PH in the tank was ideal, and the new purchased water had a PH of maybe 7.8. Anyway, I mixed in a couple of teaspoons full into the 15 gallons of new water and it fixed the problem. Good luck, Lesley
 
azeritis

azeritis

Member
Have you tested for pH the water you are using for your changes?
If not, mix salt with RO water, use a power head to aerate the water for 24 hours, and then test both the tank water and the water your are going to use at the same time.
In addition always be aware that you must test for pH AT A CONSISTENT TIME WHEN DOING THE TESTS. pH will vary from night to day (with the lowest value in the morning before the lights come on, and the highest values at night when the lights go out)
What subtrate do you have?
Test for alkalinity.
 
timsedwards

timsedwards

Active Member
Hi there,
Yes I think it is important to realise the inter-relationship between Alk-Calcium-pH. They are all interdependent. Test for Alk and let us know what you get. If you can get a good Alk reading, then that will stabilise pH.
What time of day are you testing?
When do you leave your lights on the tank on?
Use buffer as a last resort,
Best Wishes,
Tim.
 
beaslbob

beaslbob

Well-Known Member

Originally posted by toddpolish
info:
90g tank, 7g refuge, 7g in sump. amm=0, trite=0, trate=2 (yes it has cycled)
tank is 2months old - no fish yet. just royal urchin, 12 turbos, 4 red hermit crabs.
I did water change this past weekend of about 10g. my pH was 8.0 - tried to up it by doing another water change. I did one tonight of ANOTHER 10g.
an hour later and the pH is 7.7
I'm using RODI. my turnover is at least 13x.
this is irritating. why is it going down instead of up.
Very common to have ph rise on a new tank. If it stays at 7.7 I would just add a little baking soda.
 
toddpolish

toddpolish

Member
I have not tested the pH of the water-change water. I will do that next time.
I do aerate the water for 24hrs
I ordered alk and calcium tests online, should have them next week.
4-5" of pure aragonite = substrate.
 
timsedwards

timsedwards

Active Member
Let us know what the Alk-Ca results are :)
Soon as we know that we can direct you on how to get them correct and everything will be fine :) Also I think its very important to know the pH of the water change water.
All the best,
Tim.
 
toddpolish

toddpolish

Member
my tank is now around 8.0
just added salt to some RODI water and aerated for an hour. pH is about 8.2
strange
wanna get my first fish!!!
 
jlem

jlem

Active Member
RO water removes everything from the water. Most salt mixes assume that you will use tap water that has some buffering capacity and some calcium. So when you mix with RO, you usually should throw in a spoon of buffer and a shot of calcium to replace what the RO unit took out of the tap water. Baking soda will up the PH but will not do much for Alkilinity which helps the tank to maintain high PH. Buffers are a mixture of different salts and sodium bicarbonite that raises and helps maintain a high PH through high alkalinity.
 
beaslbob

beaslbob

Well-Known Member

Originally posted by jlem
RO water removes everything from the water. Most salt mixes assume that you will use tap water that has some buffering capacity and some calcium. So when you mix with RO, you usually should throw in a spoon of buffer and a shot of calcium to replace what the RO unit took out of the tap water. Baking soda will up the PH but will not do much for Alkilinity which helps the tank to maintain high PH. Buffers are a mixture of different salts and sodium bicarbonite that raises and helps maintain a high PH through high alkalinity.

I just could not resist this. LOL
Baking soda is sodium bicarbonate. Reference: www.armandhammer.com/HowItWorks/body.htm
Therefore baking soda is the active ingredient of all those expensive ph buffers sold in aquarium shops
 
beaslbob

beaslbob

Well-Known Member

Originally posted by toddpolish
anyone know what the formula for amount of baking soda per gallon????
On my 55g I just dump a little bit in right from the box. I think it is about a half a teaspoon or so. It should be about the same as the ph buffers sold.
 
broomer5

broomer5

Active Member
I wouldn't suggest using baking soda by iteslf as a pH buffer.
It's okay - but there are better ways to dose a tank in my opinion.
Just adding sodium bicarbonate by itself may throw your bicarbonate/carbonate balance out of whack.
There's more to total alkalinity than just bicarbonate & carbonate.
If you do chose to use it - at least dissolve it in some freshwater and add slowly when you top off the tank.
I would be very careful before using it alone - especially if you have corals/inverts.
 
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