pH stability question

[Archman66]

My tank just finished its cycle. Noticed pH wen from 7.0 to 7.4. I'd like to keep it on the acid side or neutral max.

For water changes during cycle, at first I was adding buffer to RO water until water was at 7.0 before adding to tank. Tested 30 mins or so after adding buffer.

Then I tried simply mixing RO and tap water (adding dechlorinator) until mixed water tested to 7.0. I would mix 2 types in a bucket, and stir it well before testing. That seemed to be working.

pH was a steady 6.9-7.0 during the last couple weeks.

I topped off the tank yesterday using the mixed water method. Only added about a gallon to 1 1/2 gallons, but pH was 7.4 today (GH 5°, KH 3°)

Will the nitrogen completing its cycle cause this?

What 's the best way to keep it stable? I can get RO water for about $1 for 5 gallonsnd don't mind doing this. I test it and the pH is too low to register, and there is no detectable KH and GH

Tap water has a pH of 8.2, KH 2° , GH 6°.

How long should I wait before testing the mixed water?

Should I mix it in advance, and store it in an 5 g plastic bottle until needed?

[dancethenparty]

i don't have much experience in cycling but i'll answer what i can. from what i hear...toping off is bad. and you just learned why; it unstableizes things.
you ph is your ph. don't try to change it with chemicals.
in fact if you want anything to be stable, don't add chemicals.

[Dave66]

My tank just finished its cycle. Noticed pH wen from 7.0 to 7.4. I'd like to keep it on the acid side or neutral max.

For water changes during cycle, at first I was adding buffer to RO water until water was at 7.0 before adding to tank. Tested 30 mins or so after adding buffer.

Then I tried simply mixing RO and tap water (adding dechlorinator) until mixed water tested to 7.0. I would mix 2 types in a bucket, and stir it well before testing. That seemed to be working.

pH was a steady 6.9-7.0 during the last couple weeks.

I topped off the tank yesterday using the mixed water method. Only added about a gallon to 1 1/2 gallons, but pH was 7.4 today (GH 5°, KH 3°)

Will the nitrogen completing its cycle cause this?

What 's the best way to keep it stable? I can get RO water for about $1 for 5 gallonsnd don't mind doing this. I test it and the pH is too low to register, and there is no detectable KH and GH

Tap water has a pH of 8.2, KH 2° , GH 6°.

How long should I wait before testing the mixed water?

Should I mix it in advance, and store it in an 5 g plastic bottle until needed?

Archman,

There's either rocks or gravel with calcium carbonate on/in them, or such minerals in your tap water, or both, which is making the pH rise.

You're correct about storing mixed water. I run an air stone for a day before using such stored water, to enrich it with dissolved Oxygen.

The Nitrogen cycle has nothing to do with pH nor hardness.

Just FYI, you should top off with just RO water. Don't mix it with tap. When water evaporates, it leaves behind everything that was in the water. The evaporated water is thus 'pure'; all minerals and metals are left behind.

The best way to keep the pH and hardness stable is to use the exact ratio of RO to tap water every time when you do a partial water change. As buying RO water can add up over time, you might think about buying you own RO or RO/DI unit sometime in the future.

What fishes are you planning to keep in that soft, neutral to slightly acidic waters?

Dave

[Archman66]

Well, I'm going to start with neon tetras, some cory's and a pair of flame gourami. After I've gained some experience and the tank becomes better established, I'd like to have cardinals and a pair of Rams, or a pair cockatoo apisto's. Hence, wanting to keep it soft.

My tap water is strange. High pH, but low hardness and calcium which worries me that there is little calcium carbonate to keep the pH stable at any level. I've added some Seachem buffer (acid and alkaline) every once and a while for that reason.

Oh and thanks for the tip on topping off with just RO water. I think that may have played a part.

[Fraoch]

you ph is your ph. don't try to change it with chemicals.
in fact if you want anything to be stable, don't add chemicals.

+1!

With water changes, RO water and buffer addition things quickly become very complicated and prone to errors and swings. With live fish in the tank this will become dangerous for them...

[MonkeyPox]

Generally speaking, fish are more tolerant of incorrect pH ranges then they are of shifting pH.

[rangur1]

your water seems more suited to alkaline fish than amazonion. if, however you have your heart set on them , i would strongly recommend a water supply tank with its own filter/heater and chemically buffer water to acid side.
ph 6.5 powder should be fine. this way you have water ready to go for water change . if you execute a 20% water change every 10 days you should have no problem with ph swings. but do not use the liquid ph adjusters! use only powder buffers, they are much more stable, IMHO. good luck

ps i kept 10 tanks 20,30,5 55g,75 ,150-all housed acid favoring tetras,rasboras,barbs,silver dollars,bala sharks,plecos,gouramis,etc and i never had issues with ph or fish health, however, i struggled when i tried using only buckets, the water holding tank was crucial,as was a testing kit.