Under-sink or reverse osmosis: test your water first

Short answer. Test or look up your water first, then match each result to a claim on the filter's list. Frizzlife sells two kinds of under-sink system: carbon-type filters (SK99-NEW, MK99) and reverse osmosis (RO) systems (PD600-TAM3, PX600). Only the RO systems state a drain ratio and need power. We have not tested any of them. This page gives information from the sources named, not medical or plumbing advice.

What your water test tells you first

Pick the claim you need before you pick the product. Our water test guide covers strips and lab kits, and your water utility publishes reports. Then read the claim line on the filter.

Your result or worry	What to look for on the filter page
Chlorine taste or odor	A carbon-type claim. Frizzlife's PD600-TAM3 page lists the carbon block as "Helps reduce chlorine, odor and unpleasant taste."
Lead or another named contaminant	A claim that names that substance, under a health-effects standard (42 is aesthetic, 53 is health effects). For a health concern, your utility or health department is the right contact.
High dissolved solids	An RO system. Frizzlife's page says NSF/ANSI 58 evaluates total dissolved solids reduction among other things.
Hardness	None of the systems here is aimed at it. See our shower filter or softener guide.

One trap. A TDS pen reads total dissolved solids, not individual contaminants. Frizzlife's own FAQ says "Regarding TDS, it is not a professional way to test water quality." It also says "please do not use TDS to test water from any source except for a Reverse Osmosis system, as the result will be meaningless."

The order of checks

Five boxes in order: read your utility report or test your tap water, match each result to the claim list of the filter, pick the type that lists that claim, check cabinet space power and drain line, keep a replacement date for each cartridge. — An illustration of the order we suggest. Built from the Frizzlife product and FAQ pages read 2026-11-01.

What the maker states, side by side

	SK99-NEW	MK99	PD600-TAM3
Type	Three-stage under-sink filter, direct-connect	Under-sink filter with a 0.5 micron element, direct-connect	Tankless RO with a remineralizing cartridge
Flow stated	2 GPM at 60 psi	2 GPM at 60 psi	0.41 GPM, 600 GPD
Drain	None stated in the text we read	None stated in the text we read	2:1 pure-to-drain ratio
Power	None stated	None stated	Spec list says "Electricity Required"
Stated filter life	Stages: 3-6, 6-12, 12-18 months	FZ-2: three figures on one page (see our worksheet)	12 and 24 months, plus the TAM3 cartridge by gallons
Testing wording	IAPMO against 42 and 53	IAPMO R&T against 42 and 53	SGS-tested to 42, 53 and 58

All of this is the maker's text from 2026-11-01. The PD600-TAM3 spec list also includes "Drill a hole in the countertop" for its faucet. The listing question is the same for all three: ask for the exact listing, as in our certification guide.

Waste water, if you read the ratio literally

A bar showing 10 gallons of drinking water plus 5 gallons sent to drain, for 15 gallons drawn from the supply line, at a 2:1 pure-to-drain ratio. — Our arithmetic. Input: the 2:1 ratio Frizzlife states for the PD600-TAM3 and PX600, read 2026-11-01. 10 / 2 = 5 gal to drain; 10 + 5 = 15 gal drawn.

That reading takes the ratio as stated: two parts pure water to one part drain. Two things the pages leave open. The PD600-TAM3 page says it saves water by up to 450% against conventional RO systems; the PX600 page says 600% at the same 2:1 ratio. Neither names the comparison system, so we cannot check either figure. And the RO FAQ says the unit flushes itself, including for 18 seconds every 6 hours in standby. It gives no volume for a flush.

Pressure and power, as far as the pages go

The PD600-TAM3, PX600 and RO FAQ text we read gives no minimum supply pressure in psi. The SK99-NEW and MK99 pages state their 2 GPM at 60 psi, so that figure assumes 60 psi at your tap.
The RO FAQ says that if the system sits more than 15 feet from a fridge or ice maker you might need a mini tank to boost pressure.
The RO systems need an outlet; the spec list says electricity is required.
We did not read a source on typical home water pressure. A pressure gauge is how you would know yours.

What the pages do not say

No test conditions for the 2:1 ratio (feed pressure, temperature, dissolved solids).
No volume for the automatic flush.
The PD600-TAM3 page says weakly alkaline water is beneficial to health. It gives no source in the text we read, and we do not repeat it.

The cheaper or simpler option

If your result is chlorine taste, a carbon filter does that job without a drain line or power, and a pitcher does it without plumbing at all. RO earns its cost when a test shows dissolved contaminants a carbon filter is not claimed for, and only if the RO model's claim list names them. If the test shows nothing you want to change, buy nothing. Ask your utility or a health agency about any health concern.

If your test points to under-sink treatment

Our reason to click: both product pages publish flow, filter life and testing wording in plain text, so you can hold them up against your own results.

We earn a small commission on qualifying sales, and 90% of it goes to charity (you can pick which); your price is unchanged. Full disclosure.

PD600-TAM3 RO systemTankless RO. The page states a 2:1 pure-to-drain ratio and lists replacement filters.View at Frizzlife →SK99-NEW under-sink filterThree-stage, no RO. The page gives a stage-by-stage replacement schedule.View at Frizzlife →

Sources

Frizzlife PD600-TAM3, PX600, SK99-NEW and MK99 product pages, the FAQ and the RO comparison page, frizzlife.com, read 2026-11-01. Maker claims.

The Frizzlife links on this page are affiliate links. We earn a small commission on qualifying sales, and 90% of it goes to charity (you can pick which); your price is unchanged. Full disclosure.

Next steps

Reading a certification claimWhat to ask before you pay.Replacement schedule worksheetPlan the cartridge changes.Frizzlife: what its pages say and skipThe whole range, dated.