high kh low ph

[kui loach]

I have a 58 gallon tank with coral; 2 oscellaris; yellow tang; baby blue tang; green chromis; snails. Everything looks healthy. Yet I get a kh of 16 and a ph of 7.7 today. I know that it is accurate because I had the same values tested at a saltwater fish store about a week ago and then the kh was 14 and ph 7.9. I am told if I add marine buffer that it will raise the ph and also the kh. Is that correct? If I add baking soda will I get the same effect? How can I raise the ph and keep the kh down? my spgr is 1.022 the nitrate is 25. I take the tank readings after the lites are on for 2 hrs so I know the ph is accurate.

Also I have had my RODI unit for about 1 1/2 years. When do I know when to change the filter?

Thanks for any input

[greg97527]

in my ro/di i replace my filters every 3 to 6 months and the membrane should be good for 3 to 5 years if its a good one. you can head over to www.airwaterice.com and get a tds meter for around 20 bucks.

[kui loach]

my tds reading is 13 and I have not changed the filter yet. I heard that it is more expensive to buy a new filter than to just buy a new rodi unit. Is that true?

Also what about my ph and kh?

[greg97527]

lol no way. what unit do you have? could u post a picture of it? how many stages is it?

[kui loach]

It is from filterdirect and I bought filters for stages 1,2,3, water general 6 stages. Do I need filters for stages 4,5,and 6?

[greg97527]

umm what are stages 4 5 and 6? mine is a 5 stage by kent marine. The Kent unit I have goes something like this:
When your feed water goes into the unit, it goes through the sediment filter first. Then it goes through the carbon block filter. After that, it goes through the membrane (the housing on top of the unit). Lastly, it goes through the vertical DI; (The last filter. It looks like it has tiny beads inside. The blue tubing is coming out of it..)

i think i paid 30-40 bucks for all my filters...sediment, carbon and di from airwaterice.com
the main membrane is more expensive though.

[dakar]

To raise the pH, set up a slow drip of pickling lime. I've been using a combination of drips of baking soda and baked baking soda to hold the Alk and pH to around 8.3 and 12dKH... The pickling lime can be substituted with Dowflake or some other types of lime (depends on what part of the country you are in as to what's available).

Why pay $20 for a little jar of 'buffer' when you can get 50lbs of DowFlake for $12, and Baking Soda runs a buck or two per pound... Make it up yourself and save big bucks.

With the RO/DI systems from FilterDirect, I have the 5 stage unit, pushed well over 5K gallons though it now, so far only changed the DI resin anytime TDS gets about 10ppm (the resin is dirt cheap), but when it comes time to change the filters it's about $50 for them, at $80 for a whole new unit.... I'll just buy a new one and hack the old one into a multi stage calcium reactor or something.

[slim]

Where are you getting a 5 stage unit for $80? How many GPD is it?

Will

[kui loach]

I am confused, I was adding marine buffer or baking soda and my kh kept going higher as well as my ph.
Also under the web site filterdirect.com, I have a RO6102dint rodi unit. Please which filters do I need? I ordered filters 1,2,3 (sedimt filter and 2 carbon filters). Do I also need a 6th stage resin filter or simply resin refill bag? Appreciate any help

[dakar]

Where are you getting a 5 stage unit for $80? How many GPD is it?

Will

Got it from FilterDirect on ebay... the new ones are 6 stage (two DI chambers) rated @ 110gpd, if you have high enough water pressure ~65psi, right now she produces about 35 gpd with a 35psi supply... waiting for the well pump to die, so I can change it over to a 4 hp jet pump and a much larger pressure tank