drop in ph and calcium

[will8]

not sure if this the right place to put this question but since i have a FOWLR i thought i would put it here. firstly the ph part iam doing a 10% PWC and i thought i would test the ph of fresh salt water, it was 7.8, why? i thought it would be the right level, 8.0-8.4. now the calcium part, i have not got any thing in my tank that using alot of calcuim so why does it drop from 420ppm (after a PWC at the weekend) to 360ppm mid week. sorry if this sounds abit thick, does the protein skimmer take the goodness out of the water as well as the bad stuff. again sorry ifs abit of a thick question

 

[cmor1701d]

If I understand you correctly, when you mix a new batch os saltwater for a PWC it tests at a pH of 7.8. Is that correct?
What SG are you mixing to?
What are you using to determine the SG, a hydrometer, a swing arm, or a refractometer?
How long after mixing are you testing the water's pH?
What brand of salt mix are you using?
How big a container of salt are you buying (25 gallon box or a 200 gallon bucket?
How are you mixing it?

Also, take a look at Solving Calcium and Alkalinity Problems.

 

[will8]

yeah thats right. mixing it to S.G 1025, using a refactometer. tested the water about 10mins after i mixed it. salt brand is Hobby, a uk make. container of salt is 22kg tub. mixs 300g. mixing it in a bucket of water with the temp at 25c. does all this make a different?

 

[Kurt_Nelson]

Is the pH of your tank correct? Is it just your freshly mixed salt water that reads 7.8? If your tank is OK, I wouldn't worry about it. I don't trust any readings I take from new salt water until it's been mixed/aerated for at least 24 hours - so 10 minutes is a little soon to test in my book.

How large of a tank are we talking about? And do you have a lot of coralline algae growth? Coralline algae will use calcium, but I wouldn't expect it to use it in the amount you're noting. Have you measured your alkalinity levels? If your alkalinity levels are out of whack, you could be precipitating some of the calcium out of the water over time. Is there white powder on your rocks at all?

Regarding the protein skimmer, no... it's not sucking out calcium.

 

[will8]

ph of the tank is between 8 -8.2. thas ok. tank size is uk 100g
yes got abit of coralline algae, my alkalinity levels are way out levels are14.7dkh, only just got a test kit. some of the LR has white powder on. i thought it was the coralline dying.
cant believe how much they is to learn. but with the help of you guys iam sure i will get there in the end.

 

[Kurt_Nelson]

Sounds like your calcium and alkalinity levels are not balanced and perhaps that's causing your ca issue. I'm guessing you're adding - or have added in the past - a buffer to try and increase your pH? That is usually where things get out of line when a tank is in the just starting up phase.

Here's a great article to help you sort things out...

Chemistry and the Aquarium

 

[will8]

yes i have been adding a ph buffer, a kent marine one. i will read the article when i have more time. thanks for the help.

 

[cmor1701d]

I see Kurt picked up for me. Thanks Kurt. Yes, all that information is necessary to determine where the problem is. As Kurt stated you really want to aerate the water for 24 hours before doing a pwc. A small power head and heater are that's required.

Probably the best thing you can do right now is make another batch of sw for a pwc. Let it sit overnight at least and then test it. If the pH, Alk, Ca and Mg are balanced do another PWC. A few 20% - 30% pwc's should get your tank chemistry back in balance.

 

[will8]

ok thanks for the advice, i will do some pwc over the next week or so. but what happens in the future when my ph drops, add buffer and run the risk of changing the calcium and alk, or dont add any buffer and went until i do a pwc and let the new salt water up the ph.
what about adding some purple up? will that help in sorting the problems out?
why is it best to let the fresh saltwater stand 24 hours before adding to the tank?

 

[roka64]

Your pH should stay consistent. You can balance it out by causing more surface ripple. I used to use a buffer, but it got to be a pain. I just added a ph near the top of the tank and it balanced out.

 

[cmor1701d]

Do you have a cover on your tank? The gas exchange O/CO2 takes place at the waters surface. Having an open top (eggcrate to keep the fish in) abnd a rippled surface if key for the gas exchange which should also help stabilize the pH. Also, the pH will vary during the day, being lowest just before the lights come on and highest just before they go out. It is important that pH be tested at the same time of day each time you test.

How often are you doing a pwc? I do them every 2 -3 weeks in my 125g tank.

 

[Kurt_Nelson]

what about adding some purple up? will that help in sorting the problems out?

Absolutely not. One of the first rules to try and stick to in this hobby is to not add anything to your tank without testing for whatever it is you're adding. The reason your alk is high is because you added buffer to remedy a pH issue (which isn't the right remedy anyway) without testing your alkalinity. Alkalinity buffers temporarily raise the pH, but only temporarily. Your best bet to resolve the issue is to find out what's causing the lower pH. Could be excess CO2 in your tank, in your house, not enough aeration, not frequent enough water changes... etc.

Adding PurpleUp at this point (and at any point in my opinion) will just throw your parameters even more out of whack.

 

[will8]

ok i wont be putting any thing in to the water.
i do a pwc weekly with out fail, change 10%.
i do have a cover on my tank, also i a rippling surface made by my protein skimmer.
checked the ph level this afternoon it was 8ppm

 

[Kurt_Nelson]

8 is perfectly acceptable. As mentioned numerous times here... stability is really more important than the actual number.

 

[will8]

thank you kurt for your help.

 

[cmor1701d]

Just be sure to check the pH at about the same time of day each time you check. That will let you know if the tank pH has actually changed.

 

[melosu58]

8 is perfectly acceptable. As mentioned numerous times here... stability is really more important than the actual number.

Kurt hit it on the head. Stability is the key.