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  1. #1
    Senior Member
    Join Date
    Apr 2004

    ph dropping please help

    Hi Everyone,

    Again I am bugging the experts in the this amazing website/forum but was wondering if I could ask a questions. My PH in my tank seems to be at 7.9. I have a 55gal tank salinity is at 1.025 and ph is at 7.9. I have been wondering about my PH so i went and purchased pinpoint meter. I calibrated it according to 25c which I had to raise the temp in my house I have been using test strips but they are inaccurate. My questions is if I do 25% water changes and gravel syphons every two weeks and I buffer the tank with seachem buffer why does it drop to 7.9 after about 7 days? I add buffer and within a day or two it drops from 8.1 to 7.9. below is what I have in my tank

    55Gal Tank
    2 Compact florecent 20Watt bulbs.
    1 emporer pegiun filter
    1 fluvo 404 filter
    1 protien skimer
    3 power heads

    Temp 82f
    salinity 1.025
    PH 7.9
    ammonia 0
    nitrite 0
    nitrate 0

    What is a good safe range of ph for a fish only tank no corals. I feed my fish only Hikari freeze dried krill. the only thing i put in my tank is Seachem buffer. Any help is apreciated. I posted a few weeks ago about my one of my fish getting fin rot and I now think it is do to the ph. Test strips sucks they are a waste of money and cause lots of problem. the water I use for my tank is RO/DI water and every two weeks after my water change I change one of the two filters filter media. I also use instant ocean salt. For testing I use a refractomter and a tropic marine hydromter for salinity testing. For PH I use test strips and now as of today a pinpoint monitor. My test strips show ph at 8.2 but the pinpoint meter with the lights off not near anything electrical becuase I read about interference says from 7.91 to 7.93. I have been running my tank for almost 3 years with just the test strips as my ph gauge and always trusted them but abviously they are inaccurate. I tested and re-tested the ph meter with the solution it came with and at 7.0 and 4.0 it came up ok. Everything was at 25C.

    Thank You for your help

  2. #2
    Join Date
    Feb 2004
    I'm not an expert but have been at this long enough to know that KH plays a big role in maintaining PH and that can be offset by your calcium/magnesium levels. The ionic balance may be out of whack. How is your KH and Calcium reading? I would also suspect that siphoning your sand bed could be depleting your ecosystem of beneficial organisms. I've never siphoned my sand bed. Not sure if that has anything to do with your PH problem though.

  3. #3
    Senior Member tiffany's Avatar
    Join Date
    Sep 2003
    Livingwaters has given some good advice.
    It would be easier to assist if we knew the ALK and Calcium levels. As your tank is 3 years old I am assuming that you have alot of pink/purple coraline algae, that uses Calcium and in return Alk and PH, fish also use calcium. So those measurements would be helpful.
    Also do you have any snails that may have died? that will affect the ph, so will any uneaten food.
    Some ASW have low magnesium (which buffers ALK, which in return buffers PH) levels and it's possible to get a 'bad batch'.
    How deep do you siphon the sand bed? It's usually best left alone, or some (including myself) will siphon the top 1 cm only every month or so. (sort of a Polish) and it is very possible that you are removing what you need for your filtration. which may affect your Ph indirectly.
    My Ph usually drops about a week after a water change, as does the ALK.
    I put this down to the low levels of ALK in NSW and the critters that live and die, uneaten matter,waste products etc....
    If your fish are getting fin rot that is usually a sign of 'bad' water quality. Or is it "fighting fins"?
    Ie: Do you fish fight?
    Do you use any additives?
    Maybe someone will be able to pitch in and offer some more advice.
    "The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
    - Albert Einstein (1879-1955)

  4. #4
    Senior Member
    Join Date
    Apr 2004

    Thank you for your reply. My alk is 3meq/l I use instant ocean salt with seachem marine buffer. I have also as of yesterday have started to use kent pro buffer to raise the alk. I do not know what my calcium levels are because I do not have a calcium test kit. I have a few dead snails and crabs but they died months ago. My fish never fight and are very friendly to eachother. I syphon the entire bottom every 2 weeks.

    Thank You

  5. #5
    Senior Member aquamann's Avatar
    Join Date
    Feb 2004
    get a test kit, its well worth the money. you have no idea what your ca level is if you don't test it.

  6. #6
    Join Date
    Feb 2004
    I generally raise my Alk to 10dkh (179ppm) before adding calcium. I try to keep the calcium between 350-400

  7. #7
    Senior Member
    Join Date
    Apr 2004
    OK finally got th calc and alk test kits here is what my tank is showing as of today about 6 hours after my water change. I also added seachem marine buffer.

    Salinity 1.024
    PH 8.27
    Nitrite 0
    Nitrate 0
    Ammonia 0
    Alk 3meq\L
    Calc 400

    What could be causing my ph to drop. I think it my alk so i went and purchased Kent Coreal Builder and am going to start using it tommorow. I tried Kent Pro•Buffer dKH but it has not elevated the alkalinity at all. Does the Kent Coreal Builder work well.

    Thank You

  8. #8
    Senior Member
    Join Date
    Jan 2004
    pH of 8.2 is normal for many tanks. What do you want your tank to stay at?

    pH is affected by CO2. This is why, at night, (the algae - including the calcareous algae - releases CO2 at night) the pH drops and during the day the pH increases as the algae uses the CO2 and releases O2. Many people drip kalk (high pH) during the night to even out this. Some people said their tank swings from 7.8 to 8.2 over 24 hours because of this. In the winter, if you have an airtight house, the CO2 level goes up in your home. This will also cause the CO2 level to increase in the water causing the pH to drop.

    A word of warning - with reef tanks, go slow. If you must add stuff (buffers, etc) add only one and then test. Don't add anything else for a few days until your tank has had time to adjust and test again before adding more or something else. If you don't go slow, you will end up with a chemical stew that will be very hard to stabalize. Unless your tank is heavily stocked with corals, you shouldn't need to add anything but your salt mix and an occasional dose of calcium or alk.



  9. #9
    Senior Member reefmutt's Avatar
    Join Date
    Oct 2003
    For a fish only system, like yours, siphoning, as you are doing is a good thing-IMO. I also think that 7.9 is perfectly alright for fish. I do think that you shouldn't be messing with all of those products together- Use one. The marine buffer has a strong effect on ph and less on alk so that is why you are seeing that ph swing- if you want it more stable and you really want to use marine buffer, try adding it twice a week.
    The pro buffer and coral builder are both designed, I think, to raise alk more than ph- and both will do the job if enough is added.
    I think that as long as your ph is staying at or above 7.9 you do not have a problem. A higher alkalinity will not necessarily raise your ph but it should keep it from swinging as much-
    My advice to you is to use an alkalinity booster ( instead of the marine buffer) get your alk to 3-4 and don't worry about the ph- unless, of course, it goes below 7.7 or something. I don't think this will happen unless as vickie pointed out you live in a sealed place that doesn't breath well--but I don't think this is the problem, as a matter of fact I don't think you really have a problem at all.......
    just raise the alk SLIGHTLY

    Old system torn down to make a playroom.. planning a 62x42x28 high

  10. #10

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