Fluctuating Ph In Cycling Tank

[fishlette]

hi all

well its been one week today since i set up my SW tank and all in all things have been going ok. i just have a couple of questions about things though.

in the tank i ave 25kgs of live rock, two collector urchins, some snails and some hermit crabs (all came free when i bought all my stuff for the tank.) i have been doing daily tests for amm, nitrites, nitrates, pH, salinity, phosphates and calcium. for the first few days all the stats were normal with pH @ 8.3, phosphates 0, calcium 540 and salinity 1.022. three days ago the ammonia started to climb to .25ppm and then everything started going all over the place.

30th -
amm .25
nitrites and nitrates 0
pH 8.1
salinity 1.022
phosphates .5
calcium 600

31st -
amm .25
nitrites 0
nitrates 2.5
pH 8.3
salinity 1.022
phosphates 1
calcium 600

1st -
ammonia .25-.50
nitrites .25
nitrates 1.0
pH 8.5
phosphates .25
calcium 620

tank is 4x18x18. running on it is a home made sump (2ft tank) with a 3800lph return pump. substrate in sump is live sand, crushed coral and this other stuff i cant remember the name of. also running an 800lph protein skimmer (soon to be upgrading to a better 1600lph skimmer...cant remember the exact stats but was reading about it the other day before i ordered it.) also has a 1200lph power head and a 500lph power head set up for current. the only life in the tank are the above mentioned urchins snails and hermit crabs. thats not counting of course the thousands of critters in/on/around the live rock

the only thing i have done to the water since setting it up is to add a little more water after we had a small leak in the return hose and lost water overnight. i mixed some IO to the same pH and salinity of the water in the tank and added it to the sump.

now this morning the pH is 8.2. these readings are definitely exact as i use a digital pH tester, not the liquid test kit one. this is my first SW tank so maybe fluctuating pH and phosphates etc is normal it just seems weird. the calcium is getting higher too. is this all normal? i dont like the swinging pH much. lucky theres no fishies in there

am i just being paranoid?

 

[scorphonic]

pH will change during a cycling process...you are using a digital pH meter? you calibrating it accuritely?

 

[fishlette]

pH will change during a cycling process...you are using a digital pH meter? you calibrating it accuritely?

yes and yes

 

[SkiFletch]

Wow, holy calcium batman! What test kits are you using? Also do you have a measure of carbonate, or alkalinity (same thing)? And most importantly, were these tests performed at the same time of day?

It is normal for the tank to go a little haywaire chemistry wise in the first week. High pH in and of itself is not a problem, yet a tank with high pH is inherently unstable. Keep an eye on it for a few mor days and see what happens.

 

[norite]

Hiya!

This thread of mine might be of use...
http/www.fishforums.net/Aquarium-Cycle-G...es-t193128.html

My tank's water chemistry went a bit weird during cycling; in particular, the pH dropped - this was probably due to the amount of biological activity giving off large amounts of CO2. The nitrates were also all over the gaff... (nitrates have now settled down to zero, and pH is a steady 8.2 ish.

Don't worry, it's normal to have 'weird' chemistry during cycling

 

[fishlette]

ok, so all over the place stats are normal

why is my calcium so high? im not sure what it should be normally to compare. i did think it must be high as with the test kit you add ten drops of the first bottle and then 1 drop at a time from the second bottle until it goes the colour specified in the instructions. the only thing i may have done wrong is, when the water first turned a shade of the end colour, it was a pale version of the colour. i kept adding until it seemed as dark as the pic on the instructions. it never seems to get quite the dark so maybe in an effort to get it that dark i added too much. dunno but if thats the case it still would be around 560-580 cause thats when it first gets quite dark

 

[SkiFletch]

Calcium, alkalinity, and magnesium test kits use a process known in the chemistry world as "Titration". Basically what happens is that the first few chemicals that you add to the test tube (the 10 drop one in this case) bind to the chemical we want to test (calcium) and often include a dye. You've basically "marked" the chemical in question (calcium). You then add dropwise a chemical that binds to the marker. When enough drops have been added, all of the markers are "bound up" and a color shift occurs. It is this point of the color shift that is critical as adding further drops just concentrates the new dye since all the calcium is bound up. You always want to note the point at which the color changes, that's the true concentration of calcium.

Having explained that, what concentration are you actually seeing? And more importantly, what test kit are you using?

 

[fishlette]

Calcium, alkalinity, and magnesium test kits use a process known in the chemistry world as "Titration". Basically what happens is that the first few chemicals that you add to the test tube (the 10 drop one in this case) bind to the chemical we want to test (calcium) and often include a dye. You've basically "marked" the chemical in question (calcium). You then add dropwise a chemical that binds to the marker. When enough drops have been added, all of the markers are "bound up" and a color shift occurs. It is this point of the color shift that is critical as adding further drops just concentrates the new dye since all the calcium is bound up. You always want to note the point at which the color changes, that's the true concentration of calcium.

Having explained that, what concentration are you actually seeing? And more importantly, what test kit are you using?

ok cool. well the calcium would be 460. i use the API calcium test kit. on the subject of test kits, the one i am using is freshwater (have ordered a marine test kit that should turn up with my order today) and some of the cards say FW/SW but some others dont. is it ok to use the FW tests or would they be giving me false readings?

 

[SkiFletch]

Hehe, depends on the kit. Calcium, alkalinity, and pH (provided it is within the right range), will all function normally for each. Ammonia and Nitrate use different color scales though.

On the subject of test kits, API are OK. Great for a beginner just getting to know things, but not the most accurate. Salifert and Seachem make really good quality test kits. If you get serious about growing stony corals, it might be wise to look into those for calcium and alkalinity

 

[fishlette]

Hehe, depends on the kit. Calcium, alkalinity, and pH (provided it is within the right range), will all function normally for each. Ammonia and Nitrate use different color scales though.

On the subject of test kits, API are OK. Great for a beginner just getting to know things, but not the most accurate. Salifert and Seachem make really good quality test kits. If you get serious about growing stony corals, it might be wise to look into those for calcium and alkalinity

excellent!! seachem is the one i ordered today. should be here by the end of the week. that is providing my wholesaler decides to send the order or sit on it and hatch it ive ordered a whole bunch of marine stuff as the previous owners didnt do much marine in the end. but since i bought the shop i will be putting in a lot more marine stuff

thanks for all your help