unable to hold low pH, please help.

[eklikewhoa]

Plants and algae will make o2 during the day(light) period and expel co2 at night(dark) period which will fluctuate the pH some.

[Ca Nguyen]

hmmm, tank A have 10 marimo balls + 1 crypt. tank B doesn't have any plants yet. i think i will do a pH test every 12 hour for the next week and see if it's a new tank thing. why do all the weird stuffs happen to me :/

[Ca Nguyen]

by the way, i can't thanks you guys enough for all the help and opinions. i love how fishbox is a wealth of information gathering

[eklikewhoa]

get a cup of your water source and let it sit out to test against that too.

[Ca Nguyen]

good idea, i've always just tested them out the faucet

[nacra99]

What is your kH? It is well worth the cost to go get a kH (carbonate) test kit. It will tell us a lot of your water and especially why you are having ph swings. Any kH of 3 or less will be prone to swing

Houston tapwater is heavily carbonate buffered, which means if you try to chemically lower the pH without adjusting the buffer, it will almost rebound to about 7.8-8 ish.

To complicate things even more, water straight out of the tap around here has a lot of dissolved carbon dioxide. Which means that if you test the water right out of the tap, and then leave it on the counter for a couple of hours and test again, you will find that the pH will have risen closer to 7.8-8 ish due to some of the CO2 dissipating.

shameless plug....

http://www.ventralfins.com/misc_articles_lowering_ph.html

[Ca Nguyen]

i seee, guess i got another thing for me to buy tomorrow. that's a really helpful article

[Ca Nguyen]

while we're on the subject, is it possible to have low pH with high kH?

i.e. pH 6.4 and kH 5?

[CRUSHER]

use a handfull of dead dried up oak leaves... boil them for about a minute or two to get them started realesing their stuff... takes forever for them to start if you just stick them in.

in my shrimp tank A (10 gallons), i use 2 inches of fluval shrimp stratum. 100% tap water, which i tested to be 7.4. pH started at 6.8, after 4 days, i'm at 7.2.

in shrimp tank B (10 gallons), i use 2 inches of ada aquasoil amazonia ii. 50% RODI, 50% tap water. pH was initially 6.6 last night. woke up today did another test and found pH at 7.4.

in shrimp tank C (20 long), i use a combination of eco complete and fluval shrimp stratum at 50/50. 100% tap water initial test was 6.4, after 2 months, it now read 7.4.

tank D (5 gallons), i use GEX shrimp substrate imported from japan. 100% tap water. initial pH was 6.6, i am on my 6th month, and pH is now at 6.8.

tank E (2.5 gallons with actually 2 gallons of water), i used black sand, and pH i 7.4 just like tap water as i expected and wanted.

why am i not able to keep pH low? i don't have the mean to test for GH and kH. i thought about using 100% RODI, but i didn't want to soften water to the point my shrimps would suffer.

[Ca Nguyen]

use a handfull of dead dried up oak leaves... boil them for about a minute or two to get them started realesing their stuff... takes forever for them to start if you just stick them in.

is this going to stain my water? i never thought about boiling the leaves before. good advice

[nacra99]

while we're on the subject, is it possible to have low pH with high kH?

i.e. pH 6.4 and kH 5?

It is only possible to achieve that if you inject Co2 or somehow replace the carbonate buffering capacity of the water with something else.. say phosphate buffers (which would mean playing with chemicals).

Here's a table for reference...

http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html

even if if you have the max ambient C02 level of about 5 ppm, (even if you push it to 10 ppm), you will not be able to normally achieve anything less than pH 7.1 or 7.2 without some sort of chemical change to the water (using buffers or indian almond leaves or peat etc).

conversely, if you want to achieve a pH of 6.4 with kH of 5.5, you will have to dissolve enough co2 to kill everything in the tank. (35-40 ppm will start becoming lethal to fish).

[Ca Nguyen]

i see, i feel like i've learn so much about kH in the last 3 days than i have in that last 4 years.

[Ca Nguyen]

ok, the amazonia ii powder tank and the eco complete/fluval shrimp stratum tank is sorted out.

amazonia ii powder tank have been at pH 6.0 or lower. if it is lower, i wouldn't know due to test kit (we all know api's limit)

the eco complete/fluval shrimp stratum tank is sitting at 7.0.

now, the only thing left is this tank with fluval shrimp stratum. last 3 days i've notice consistently.
7am = pH 6.4
1pm = pH 6.4
7pm = pH 6.4
1am = pH 7.4
this tank have NO co2, only driftwood, 10 marimo balls, 5 crypts, and a banana plant.
light on from 12pm to 5pm
ammonia .25
nitrite 0
nitrate 0
temperature 76 degree.
this tank isn't done cycling, just trying to figure out pH swing.

[Ca Nguyen]

all stable now. guess shrimp stratum just need a while to work it's buffer.

amazonia ii is 6.0 or less, not sure if that's too low for crystal shrimps.

shrip stratum is 6.6, can't be happier