lowering ph

Discussion in 'Water Chemistry' started by discusdean, 27 Feb 2008.

  1. discusdean

    discusdean Member

    Messages:
    32
    Location:
    berkshire
    Not sure if this is the right place for this but here it is anyway(ha ha)

    have taken the advice from ceg and others and started dosing dry ferts ei style and have started to see a down ward trend in ph from 7.2 to 6.4 day times slightly lower in the night hours.
    Am starting to get worried that this is not good ,

    am still only dosing co2 during the day and at a rate of 1-2 bps
    The exel and ferts are working on the plants and algae lovely but the ph is not good could anyone give me some incite into this

    many thanks

    dean :?: :?:
     
  2. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi Dean,
    When CO2 is added to water, a small percentage of this gas converts to Carbonic acid. This is how your drop checker works, by measuring the pH of the water due to the carbonic acid in the vial. This is inevitable and there is no danger to fish at all as a result of the pH drop. I guess I don't agree that the pH drop is not good. Aren't discus found in low ph waters in the Amazon tributaries? I've kept discus and dwarf chiclids for years with this method and I've never seen any ill effects, and neither has anyone else that I know of. The only danger of adding CO2 to your tank is asphyxiation of the fishes. I personally wouldn't worry about pH drop and I would even go as far as to say that I welcome it.:wideyed:

    Hope this helps.

    Cheers,
     
  3. discusdean

    discusdean Member

    Messages:
    32
    Location:
    berkshire
    i would agree with you on the discus front but was concerened that a low ph would harm .
    but may be i was wrong as i have kept marine for so long a ph swing like that is to be avoided at all cost.

    what would be concidered to low if there is such a thing with plants .

    chreers for the advice the other day am dosing now and the exel is working a treat on the algae (all turning red) and the growth has increased so again thank you.

    dean
     
  4. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    There are some Amazon tributaries with plants growing in them that have pH as low as 5 or lower :wideyed: When the rainy season arrives the flood plains swell and the forest fills with water. Leaves that have fallen then decay and release huge quantities of tannic acids. The massive pH drops often signal the onset of the breeding season so the plants have no practical pH limits on the acidic side. I've run planted tanks for breeding Apistos down to 5 without any issues. I think Eds also is heavily into dwarf chiclids and he runs low pH tanks. I've not kept plants at waters on the highly alkaline side so I can't say what the limits are there. In either case, for our intents and purposes you can safely ignore the daily pH swings or the actual pH values, either for the fish or the plants. What you absolutely don't want to do is to use pH buffers to try to counteract the swings. Salt water is a completely different animal. Fresh water is much more forgiving in almost every aspect. 8)

    Glad to hear the new fert regime is working. :D Keep it up mate! You'll whip that tank into shape in no time.

    Cheers,
     
  5. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    As Clive says I've run some very low pH tanks for killies and dwarf cichlids and never really had a problem. I just keep an eye on the KH, GH and TDS (very irregularly) and if the fish are helathy and breeding then I don't worry. I was running one tank for some killies with a TDS of about 40 and a pH of 4.3. They were breeding fine and one beaten up female Pelvicachromis added to the tank healed in amazing time!

    IME CO2 injection will lower the pH by about 1 degree and the swing of pH doesn't effect the fish at all. I think any reported problems with unstable pH are actually due to rapid swings in the water chemistry and pH is merely an indicator of these changes.

    Just set up your water conditions how you want them for the fish and ignore the pH change due to CO2 IMO.
     
  6. discusdean

    discusdean Member

    Messages:
    32
    Location:
    berkshire
    cheers guys,

    ceg the tank is much better after your advice with regards the algae and the growth is increasing what lighting would you suggest upgrading to i have 2x 52w t5 and 1x 32w t8 at the minute

    have noticed the Ph swing is worse around Sunday Monday according to my computer so am associating this with water change ,what do you guys do to your water prior to a change maybe this is where the answer lies.


    many thanks
    dean
     
  7. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    I let it warm up a bit after taking it out of the barrel in the garage and add a bit of Seachem Equilibrium or RO Right to add GH to the pure RO water. That's it. If I tested the pH I'm aure it would change, but if the fish don't seem stressed (and mine love the new water coming in) then why worry about it?
     
  8. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi dean,
    You are absolutely correct in that the pH swing is greater on water change day since most peoples tap water is neutral to slightly alkaline. Like Ed says, if you are using RO water just add whatever GH corrections you need to, and then add the water to the tank. I don't use RO so I just stick a garden hose in the tank and turn on the tap. I'm not sure what other "answer" is necessary. I think I measured my pH a couple of months ago last I recall. It was somewhere around 6. pH or it's swings are simply not an issue.

    The amount of light you add is optional. We'd have to know the tank size to offer a suggestion, but I always liken adding more light to increasing your car's speed on the motorway. From what I recall I believe you indicated having a 500 liter tank (125 USG). More light means more risk of algae. 2.5-3 watts per USG of T5 is enough to grow just about any plant, but if you don't add enough CO2 and/nutrients you can easily turn your tank into an algae farm so I would add more light carefully and slowly. 125USG should have not more than about 375 watts T5 with reflectors. If you have 100 watts T5 and 100 watts of T8 then I count that as roughly 150 watts T5 (I reckon T8 is about 1/2 as intense as T5 - not a super accurate calculation, just roughly speaking.)

    If you go to 375 watts T5 level of lighting you then need to upgrade your filtration. A good target would be to have a filtration throughput rating of 5000 liters per hour. A tank that size lit with that amount of light would easily consume 10 kg of CO2 per month. If you wanted to use less CO2 then you would consume more Excel.

    Water change schedule would also have to be upgraded to not less than 250 liters per week.

    As you can see, this is like doing 100mph on the motorway. Everything gets accelerated, risk and reward. If you want to go for it then first try adding another 100 watts T5 and see how it goes for a couple months. Remember to increase all the other items proportionally though.

    These are not absolute numbers, just ballpark figures to get your head wrapped around the ramifications of increased lighting.:wideyed:

    Cheers,
     
  9. discusdean

    discusdean Member

    Messages:
    32
    Location:
    berkshire
    cheers ceg was just checking as regard the water changes as i am now doing the same as you and using a garden hose on a slow fill,so cheers for the clarification

    the lighting issue is that as i am now dosing as per your advice and the algae has died right back i was thinking of changing the t8 to a twin t5 unit so the total wattage would go from 134w to 200 watts using reflectors what difference would this make and would i need to change slowly eg mask one tube for a few days and not at reflectors for a week or two.

    after a few better calculations and some finer measurements of displacement i believe my actual water volume is around 410 litres a little lower than thought for this size tank .

    I have increased the filtration as you suggested but only up to around 3000lph at the min and extra flow seems to help as tank much clearer.

    one last thing if you dont mind im dosing around 1bps co2 and my permanent test shows a green ok but i am not using a 4kh solution in the test vial dose this really make that much difference.


    as always any ones advice is always recieved with thanks and will post some pictures as soon as i get chance to see what you think.

    dean
     
  10. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi dean,
    OK, the algae growth has been arrested so that means the plants are healthy and that your dosing is on par. A 75 watt increase in the lighting should be fine, but again that means you'll need to tweak the CO2 a little bit. In my opinion you should forget about actual water volume for lighting calculations. This is also true for basic dosing calculations unless you have a very large sump.

    If you are not using 4 dkh water in the drop checker your readings in the drop checker are meaningless and would only be valid by sheer luck. As discussed before, you are not likely to get away with this as you start to ramp up the lighting. Get 4 dkh water ASAP, and increase bubble count to say,1.5 bps as soon as those extra watts go on is my advice. Don't risk negating the gains you've just made. :rolleyes:

    I know this probably sounds like fanaticism but plants never get enough CO2 under water and most of our problems are centered on this very important parameter.

    Cheers,
     
  11. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    It kinda depends on what KH your water is in the drop checker!!!! And that there are no other chemicals in the water to effect the pH. BTW I made my own 4dKH solution by adding Baking soda to RO water and testing it on larger test samples to up the accuracy of the KH test kit. Seems to work pretty well for me!
     
  12. discusdean

    discusdean Member

    Messages:
    32
    Location:
    berkshire
    cheers guys

    ceg your the man, have ordered the 4kh solution and upped the co2 in anticipation of a light upgrade .

    should i just turn them on or increase gradual over a week or two ?

    Also tried reading the thread ei dosing and not sure if im meant to be increasing the fert dosage at all or if the amount you recommended the other week is a max fert level with water changes.

    The tank is coming along great guns it is not up to the standard of many on here but hey we all got to start some where.


    dean
     
  13. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    If the increase in total lighting is only 75 watts or so over the previous set then just turn them on. As long as the CO2 concentration matches the lighting you are OK. Each lighting level creates a certain demand for CO2. Higher light -> higher CO2 demand. If the higher CO2 is not available the plant slowly disintegrates and algae then pounces like a vulture.

    When you dose EI you are dosing a theoretical maximum. The valuse I gave you were from an EI calculator so they should be valid even for this increase in lighting. You would only make adjustments if you needed to. For example, if you saw BGA with this new lighting after a few weeks it would tell you that you need more KNO3. You have to carefully observe the tank and make an assessment because no two tanks are alike, but the signs of deficiency in all tanks are alike (if that makes any sense). If you start to see other algae types, each type would indicate a fault in the dosing scheme or in the CO2 application.

    You can't compare your tank with others right now. The first priority is to learn how to grow the plants. After you can do this effortlessly you ascend to the next level and can plan aquascapes, or to grow more difficult plants with confidence. Use the images you see as inspiration, not as a measuring stick. 8)

    Cheers,
     

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