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Please help with tap water ph vs tank water ph. Need some advice :)

798 Views 11 Replies 7 Participants Last post by  philipraposo1982
So I have had the 75g up and running now for 12 days (tank is cycled).
heavily planted with alot of DW
fish are:
2 golden rams
2 pearl gourami
25 cardinal tetra

I test my tank ph and it seems to sit at around 6.4-6.6. This is fine for my fish.
I test my tap like right from the tap and it shows 7.8

I fear that with doing WC's I am going to be creating to much of a PH swing, I don't want to cuz harm or stress to my fish if I don't have to.

Lets assume I do 15% wc weekly, how do i know how much of a ph difference this will cuz to my tank? i can't imagine it would go up to 7.8 but maybe 6.8 maybe 7? i don't know...

Anyone can hazard an experienced guess? What would you guys suggest I do to handle this situation? Because I plan to keep my tank under stocked and I have alot of plants and a big filter I would imagine I don't need to do WC's often. Which is probably a good thing as I don't want to be fluctuating my ph at all if possible.

I am trying to figure out whats a safe amount (%) to do as water changes.
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Tried letting your tap water sit out for 24 hours and testing again? Sometimes the results will vary.

Personally, I'd just do daily big water changes to try and slowly get your tank closer to your tap parameters. Your driftwood and substrate are probably pulling the pH down, and the effect is probably temporary anyways. 7.4 isn't terribly hard, even for those fish species, especially if they are captive-bred versus wild-caught (the Cardinals are probably WC, but they others CB).

Your other best option would probably be to invest in an RO unit.
why would i test after 24 hours if i do water changes with water right from the tap?
i want to keep it were it is. trying to bring it up with all my dw only pulling it down would be a losing battle imo.

i just want to know how doing water changes is going to effect my ph. if i do 15-25% any idea of what the end ph would be?
Because there could be gasses and solids in the water straight from the tap that will outgas/precipate out after 24 hours. In other words, the reading straight out of the tap might not be all that accurate- another possible factor between the difference in readings you're getting between the tap and tank.

If your driftwood and substrate are pulling the pH down that far after only 12 days, that effect most likely is only going to be temporary.

What kind of substrate are you using?

Also- are you injecting CO2? If you are, then you need to set some tank water up for 24 hours to let the CO2 outgas before testing.

Do you know your kH and gH readings? Those two are actually much more important parameters for livestock, anyways.

(PS- I realize I keep asking you more questions without answering your original question... but until we understand exactly what's driving the fairly dramatic pH shift that's occured in the 12 days since you filled this tank, I don't think we CAN accurately answer your question...)
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i understand what your saying but i mean like in the 24 hours that the ph is still high, i fear that it will bring up my ph in the tank to much and kill my fish

i don't use c02
You won't kill your fish like he said above it is just your driftwood and other factors in your tank. That will go away and to do a 15 to 20% water change won't hurt anything. Now if you want to be that picky about it you could get a RO or RO/DI unit and purify your water but you will have to buffer the water with treatment to replace what the RO or RO/DI unit takes out to the levels you want *YOU CAN'T JUST USE RO OR RO/DI WATER THAT WILL KILL YOUR FISH*
I think you may have fallen into a trap that the hobby has created for us. There is a huge stream of info saying that PH is a critical item for fish health. It seems to be one of the main points we read about.
Buy then there are also many sings that this may not be true. Take as an example, African cichlids. Among the first things we read is that they have to have hard alkaline water to do well. But a number of this group find this is not the case for our fish. I find my is doing quite well and continue spawning when I have added CO2 and gradually driven the PH down from 7.8 to as low as 6.8. A full point in PH drop. In fact using a controller to read the PH so that I feel I am getting a reasonably accurate reading, I find the PH in a tank varies quite a lot from day to night when CO2 is not running.
So the question becomes whether PH is really that important item that we are all reading about?
I congratulate you on wanting to do the best for your fish but then I feel you may be somewhat mislead by advise you read. I would not follow PH as the guiding light that it may seem to be. I am finding that the water hardness may be a much more important factor.
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I would put the test kit away, change water each week at 25 to 30% .
The water from tap will mix with water in the tank and this change would not be enough to worry bout given that 70 to 75 % of the tank water will still be softer than the tap.
PH is not as important to the fishes as sudden changes in GH.
With smaller water changes /more frequently the difference would not be enough to worry bout with fishes mentioned,as would a large 70% water change.
Now spawning is another story.
Lets assume I do 15% wc weekly, how do i know how much of a ph difference this will cuz to my tank? i can't imagine it would go up to 7.8 but maybe 6.8 maybe 7? i don't know...

I think the only way you'll know is to do a water change and test again to find out!

But I think you've already been given the best advice by everyone above me.

I will say that I recently set up my first planted tank with a dirt substrate and some driftwood. I've had other tanks up and running for quite a while and hardly ever saw a pH of anything other than about 7.6 or so. Then in the dirted tank with the driftwood I was getting readings of 6.8 or so after having the tank filled for about a week or two. (no co2 and no effort on my part to change the ph). Now a few weeks later the ph in the tank seems to have stabilized back at around 7.4-7.6
My tanks ph dropped as low at 5.5 my probe told me when I had some rotting manzanita in it. My tap was neutral and I do 50% water changes weekly. My fish were all completely fine with this and I fill right from the faucet using my python.

I've since removed the manzanita in favor of some other driftwood and my ph rose back to 6.4 during the day and around 7 at night. Fish are still completely fine with water changes. As others mentioned, it's not that big of a swing when it's mixing with the other water in the tank already.
ok thanks.
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